In January 2024, the state of Maine's, USA, coastline experienced multiple storms that caused extensive damage to public infrastructure and private property. The town of Wells, which encompasses the Webhannet and Ogunquit estuaries, suffered damage to “grey” coastal defenses, such as seawalls, bulkheads, and riprap, which were breached and therefore not able to protect roads and buildings. Failure of traditional defenses has partly motivated a growing interest in nature-based solutions, in addition to the range of ecosystem services these natural systems can provide, for enhancing protection along Maine’s coastline in areas where the adoption of such “green” solutions is  feasible. Saltmarsh restoration, for example,  is an approach that aims to bring back degraded ecological function of a tidal marsh, while simultaneously providing increased flood protection. In this study, we develop a LISFLOOD-FP model for the town of Wells using high-resolution (~1m) DEM and land cover datasets. We validate the model through satellite imagery such as Sentinel-2 data. We use the model to map the inundation extent in Wells during the January 10^th coastal storm and to estimate flood exposure of the built environment. Next, we simulate the restoration of the tidal marsh within the two estuaries and assess its ability to reduce the flood footprint of the January 10^th storm. To this end, we identify megapools suitable for drainage, thin layer placement, and revegetation, and therefore modify the model’s elevation and roughness coefficient in these targeted areas. Our study evaluates the effectiveness of pool-to-marsh restoration as a nature-based approach in decreasing flood depth and velocity near adjacent buildings and roads.

How to cite: Boumis, G., Hamidi, E., and Spencer, T. B.: Coastal flood impacts on the built environment in Wells, Maine: Assessing the effectiveness of pool-to-marsh restoration in reducing exposure, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-131, https://doi.org/10.5194/egusphere-egu26-131, 2026.

Nature-based coastal solutions (NBCS) are increasingly recognized as effective, adaptable, and multifunctional approaches to mitigating coastal hazards while supporting ecological, economic, and social co-benefits. Despite a rapidly expanding evidence base, scaling of NBCS from localized interventions to regional, systems-level applications remains a fundamental challenge, particularly for long-term planning under accelerating sea-level scenarios, increasing storm intensity, and complex governance environments. This paper presents a comprehensive, interdisciplinary case study of Deer Island, Mississippi (USA), an Engineering With Nature® (EWN®) project that illustrates how integrated science, engineering, landscape architecture, and strategic partnerships can support the design, quantification, and implementation of NBCS at scale.

Deer Island represents a decade-long collaborative effort involving federal, state, academic, and non-profit partners working to stabilize eroding shorelines, restore degraded habitats, and strengthen the island’s overall geomorphic and ecological resilience. A central component of the project is an extensive data-collection program designed to quantify “as-is” island conditions and constrain uncertainty in future performance predictions. This includes topo-bathymetric surveys, sediment coring, vegetation mapping, and hydrodynamic and morphodynamic monitoring. All variations of work that build on the state-of-the-art techniques described in recent coastal resilience literature and research produced by the U.S. Army Corps' Engineering With Nature (EWN) research program. These datasets provide the empirical foundation for both the engineering design and the landscape architectural vision, ensuring that proposed nature-based features are grounded in site-specific processes.
Landscape architects worked alongside engineers and scientists to develop multifunctional NBCS designs that rebuild critical marsh, beach, and dune systems while enhancing habitat connectivity, recreational value, and long-term adaptability. These design concepts were translated into quantitative performance assessments using process-based numerical models that simulate storm surge attenuation, wave energy reduction, sediment transport, and morphological evolution under present and future climate scenarios. These modeling results demonstrate measurable risk-reduction benefits at both the island scale and the broader Mississippi Sound region, underscoring the importance of designing for system connectivity rather than isolated features.
A defining strength of this project is its collaborative, multi-sector governance structure. Regular engagement among engineers, ecologists, coastal managers, landscape architects, federal and state agencies, universities, and local stakeholders enabled iterative refinement of design alternatives, strengthened regulatory alignment, and ensured that both engineering and ecological performance criteria were jointly prioritized. This partnership-driven approach reduced institutional barriers, improved long-term maintenance planning, and provided a replicable model for other regions seeking to scale NBCS through coordinated decision-making.
Deer Island will has entered the construction phase and is marking a critical transition from concept to implementation, and will be monitored for years following. As one of the largest engineered NBCS efforts in America's Gulf waters, it demonstrates how integrated data collection, process-based modeling, and collaborative landscape-informed design can materially advance long-term resilience, reduce uncertainty, and provide transferable pathways for scaling NBCS across diverse environmental and governance contexts.

How to cite: Tritinger, A., Crisanti, S., Bailey, S., Berkowitz, J., Godsey, E., Suedel, B., and King, J.: Upscaling Nature-Based Coastal Solutions Through Integrated Design: Collaborative Data, Modeling, and Landscape Design for the Deer Island EWN Project, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-314, https://doi.org/10.5194/egusphere-egu26-314, 2026.

Salt marsh restoration can be considered an essential nature-based solution for coastal protection and climate change mitigation. However, restoration practices present a myriad of challenges, particularly in the journey from seed germination to achieving climate resilience, as response to challenges such as variable hydrology, and climate change impacts that can hinder seed establishment and growth. Effective restoration requires a deep understanding of the local ecology, the selection of native plant species, and adaptive management strategies to foster resilience against rising sea levels and shifting climate patterns. Active restoration is used less often than passive restoration, and involves improved seedling and planting techniques, with a drawback related to the physical damage done to healthy habitats through the collection of donor plants. A recent alternative solution to counter this destructive issue involves the installation of a plant nursery (mesocosms) for seed germination and plant production.

In this study, we present the experimental design and preliminary data on halophytes’ germination and seed propagation strategies, conducted in a mesocosm conditions.  Our goal is to assess the optimal abiotic conditions to initiate the germination process of Atriplex Portucaloides seeds (mid-high marsh species), collected at Ria de Aveiro coastal lagoon (centre Portugal). Simultaneously, this study provides valuable insights into the climate resilience of Sporobolus maritimus (low marsh species) under increasing flood conditions, framed within various sea-level rise scenarios. Through fieldwork experiments at the Ria Formosa lagoon (south Portugal), data on the plant's adjustments to prolonged hydroperiods have been recorded. Adjustments in growth patterns and survival rates of Sporobolus maritimus are crucial for understanding the plant's response to environmental changes and provide essential information for estimating the longevity of restored populations. By addressing these two challenges, the obtained results enhance knowledge and support the development of effective restoration strategies to enhance the resilience of coastal salt marsh ecosystems against climate change.

Keywords: salt marshes, halophyte nursery infrastructure, sea-level rise, field experiment, resilience.

Acknowledgments: This study had the support of the Fundação para a Ciência e Tecnologia (FCT), through the strategic projects UID/00350/2025 (CIMA), UID/50017/2025 (doi.org/10.54499/UID/50017/2025) and LA/P/0094/2020 (doi.org/10.54499/LA/P/0094/2020) (CESAM- Centro de Estudos do Ambiente e do Mar). Inês Carneiro by was supported by the PhD grant 2024.02443.BD, also funded by the FCT. Thanks are also due to FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2030 and by Portuguese funds through FCT in the framework of the project COMPETE2030-FEDER-00929100 (BLUE-REWET).

How to cite: Carneiro, I., Sousa, A. I., Koppel, J. V. D., and Carrasco, A. R.: Challenges on salt marsh restoration: from seed to climate resilience, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-885, https://doi.org/10.5194/egusphere-egu26-885, 2026.

Mangroves help protect coastlines from storms in many regions around the world. However, less is known about how changing storm activities may influence this protection. Using global storm records and a transparent computer model, we examined how cyclone patterns have changed over recent decades. We found that between 1981–2000 and 2001–2020, mangrove exposure to cyclones increased by 13%. Importantly, the type of cyclones affecting mangroves has also changed: slow-moving cyclones have become much more common in the Caribbean, while fast-moving cyclones have increased in East Asia. These changes can affect how mangroves are damaged and how well they can continue to act as natural barriers against storms. Our findings highlight the need to consider changing storm behaviour when using mangroves as nature-based solutions for coastal protection under climate change.

How to cite: Mo, Y., Hall, J., Baldwin, A., Simard, M., and Donohue, I.: Mangroves as natural storm protection: How changing cyclones affect their role, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2801, https://doi.org/10.5194/egusphere-egu26-2801, 2026.

Enhancing Biodiversity Through Repurposing Manmade Structures with Secondary Coatsal Benefits

Authors: Henric Schmidt1, Nicoletta Leonardi1, Darryl Newport2, Andy Plater1,Stephen Roast3

Affiliation: 1University of Liverpool, UK; 2University of Suffolk, UK. 3 Sizewell C, UK.

The decommissioning of coastal nuclear power stations, such as the Magnox site at Sizewell A, offer a critical opportunity for coastal management. Traditionally, decommissioning involves the removal of large radioactive components making the decommissioning dangerous and expensive however, these degrading materials offer significant untapped value for boosting biodiversity in nearby marine environment by providing habitat for flora and fauna furthermore these artificial reefs are effective at reducing coastal erosion and providing flood protection. This research investigates the feasibility of repurposing decommissioned nuclear infrastructure to serve a dual purpose: reducing coastal erosion and providing flood protection through wave energy dissipation and enhancing marine biodiversity by providing shelter for marine life.

To accurately assess the feasibility of this project, this study employs a three-pronged methodological approach. First, Computational Fluid Dynamics (CFD) will be utilized to model various structural orientations and reef designs, identifying which configurations maximize both wave energy dissipation and the creation of low flow rate areas which are required to induce biodiversity. Second, on site visits and SCUBA dives at Sizewell A will be conducted to establish a current ecological baseline and assess the existing structural condition. Finally, findings from the digital models and field observations will be validated through laboratory emulation, using scaled physical models in a wave tank to test the most promising designs under controlled hydrodynamic conditions.

By integrating digital simulation, field observation, and physical experimentation, this research aims to bridge the gap between nuclear decommissioning and coastal engineering. The project seeks to provide a framework for the effective utilization of legacy concrete structures, such as those found at Sizewell A. Furthermore, this research will provide insights into "Design for Decommissioning," potentially influencing the structural design of future nuclear plants to facilitate repurposing for marine applications. Ultimately, this work aims to provide a scalable model for how the nuclear industry can contribute to a more sustainable and "nature-positive" future, transforming industrial liabilities into resilient ecological assets that also protect vulnerable coastlines.

How to cite: Schmidt, H.: Enhancing Biodiversity Through Repurposing Manmade Structures with Secondary Coatsal Benefits, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3937, https://doi.org/10.5194/egusphere-egu26-3937, 2026.

Currently, a substantial proportion of power stations, railway infrastructure, wastewater treatment facilities, and residential areas are at risk of coastal flooding, resulting in significant annual economic losses. Hard engineering solutions are becoming economically unviable due to the high costs of construction, maintenance, and adaptation to changes in sea level and storms.

For this reason, there is a growing interest in engineering with nature (including the creation of salt marshes, seagrass beds, beach nourishment, and mega-nourishment), which offers a more economically viable alternative and supports net zero-carbon emissions and local amenity value, as highlighted in the 25-year Government Plan to Improve the Environment and the FCERM strategies for England, Scotland, and Wales.

However, despite the growing recognition of the necessity to move towards this greener alternative for coastal protection, there is still limited guidance on the implementation of engineering with nature compared to hard engineering solutions. There are no quantitative and process-based decision-making tools or guidelines to aid engineers, planners, and governments in selecting coastal management strategies suited to their unique local environments. There remain many uncertainties regarding the conditions that maximize the establishment and longevity of engineering with nature, as well as uncertainties regarding its effectiveness.

The project ENARM develops novel understanding necessary to protect coastal infrastructure and coastal communities through the widespread adoption of engineering with nature. ENARM uses a novel combination of remote sensing, artificial intelligence, and computer models to provide, for the first time, design criteria for coastal protection using engineering with nature, as well as the knowledge necessary to select the most durable and efficient coastal management type and location.

Results are summarised into interactive decision-support tools, to enable a consistent evaluation of the pros and cons of different coastal management interventions, including uncertainties related to their effectiveness under different sea-level rise and storm scenarios.

How to cite: Leonardi, N.: Combining Artificial Intelligence, remote sensing and computer modelling for the design of Nature Based Solutions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7898, https://doi.org/10.5194/egusphere-egu26-7898, 2026.

How to cite: Green, S., Hanley, N., Hurst, M., and Naylor, L.: Redefining Our Urban Boundaries: Valuing Development Pathways for (Peri)Urban Vacant and Derelict Land, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10982, https://doi.org/10.5194/egusphere-egu26-10982, 2026.

Climate change is continuing to affect coastal regions through rising global sea levels and evolving storm conditions, while land subsidence further amplifies relative sea-level rise in many low-lying areas. Coastal hazards arising from the combined effects of waves and high water levels are increasingly exposing areas to erosion and flooding. In this study, a low-lying region along the coast of Boundary Bay in British Columbia (BC), which is exposed to waves and storm surges, is studied. Communities and critical infrastructure in this region are protected from flooding by an existing 100-year-old dyke, which was not designed to account for sea-level rise. The “Living Dyke” is a pilot study implemented by the City of Surrey, BC, to assess and demonstrate the viability of nature-based infrastructure solutions to enhance coastal flood protection in the region. The project involves placing sediment and planting native salt marsh vegetation to test four stabilization techniques including brushwood dams, a sand berm, rock berm, and oyster-shell bags within the intertidal zone to attenuate waves and reduce wave overtopping of the dyke. In collaboration with biologists and ecologists, adaptive management, monitoring, replanting, and brushwood dam repair has occurred since construction in 2023. A series of in-situ pressure sensors have been deployed to monitor wave and water-level conditions at the field site. Using the observations, a high-resolution numerical model (XBeach) is calibrated, validated and applied to simulate storm events and flooding scenarios at the Living Dyke. Modelling of major wave events and sea-level rise scenarios is conducted to evaluate the performance of the different stabilization techniques. The results provide insight to the potential benefits of the Living Dyke as a nature-based technique to mitigate coastal squeeze and reduce the combined impacts of waves, storm surges, and sea-level rise. Ultimately, the interdisciplinary results integrate to provide the City of Surrey with guidance on the implementation of a field-scale nature-based infrastructure solution along the dyke.

How to cite: St. Marseille, M. M. J., Mulligan, R. P., Gauk, J., Murphy, E., and Provan, M.: Modelling combined wave and water-level hazards at a nature-based infrastructure site in British Columbia, Canada, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13833, https://doi.org/10.5194/egusphere-egu26-13833, 2026.

The analysis to be presented is focusing on the importance of the large historical regional variability and large recent temporal variability of mangrove processes along the Mekong Delta Coast. Such variability is insufficiently recognized in literature. Existing research and proposed solutions are often targeting specific provincial issues, presenting local not thoroughly tested solutions, and more importantly that are not generally applicable to other regions and sometimes even detrimental for other regions.

A thorough description is given of the longer-term differences in geography and physical processes, on centennial scales and on more recent, decade-scale human impacts on the various coastal regions of the Mekong Delta. For each of these regions, we present an analysis of the above-mentioned aspects, based on geological, historical, and recent observations of coastal evolution. Current physical process insights on mangrove dynamics are discussed, while including recent and expected impacts of human-induced and climatic change-induced impacts. A most pivotal finding is the quite recent occurrence of a tipping event causing the Mekong Deltaic Western Coast and parts of the Mekong Deltaic Eastern Coast turning to extreme erosion while having been stable over 100 years in the last century.

Our analysis aims to elucidate the profound geographical and temporal variability of coastal mangrove processes along the Mekong River Delta. This provides important information for new research studies that are welcomed strongly to support Vietnam in its quest to solve mangrove issues along the Mekong Delta Coast in a sustainable, nature-inspired manner. The Mekong Delta is of paramount national importance in an economic sense, and at least as important the delta is home to nearly 20 million inhabitants, who have their livelihood based on the coastal region.

How to cite: Phan, H. M., Stive, M. J. F., Phan, L. K., Truong, S. H., Dao, T. H., and Le, T. H.: On the importance of recognizing the large regional and temporal variability of coastal mangrove processes along the Mekong Deltaic Coast, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15854, https://doi.org/10.5194/egusphere-egu26-15854, 2026.

Compound flooding in urban coastal areas is expected to become an increasingly costly problem due to projected sea-level rise throughout the 21^st century. The emergence, and increasingly widespread acceptance, of “green infrastructure solutions” in recent years provides a wider range of adaptation measures compared to traditional gray infrastructure alone but comes with additional challenges. First, the impact of green infrastructure on flood risk is less straightforward to quantify relative to the augmentation of hard structures. Second, the net economic impact of green vs gray infrastructure in the form of flood reduction and associated ecosystem co-benefits is difficult to compare. Here we present a cost-benefit analysis of different sea-level rise adaptation options for Coos Bay, Oregon, U.S., which each incorporate different degrees of wetland restoration (green infrastructure) and levee heightening (gray infrastructure). For each scenario, continuous water level predictions are produced over the period 2020-2100 by pairing a physically constrained hybrid harmonic tidal water level model with stochastically modeled storm surges and a simplified wind wave runup model. Property damages and transportation delay costs are then calculated for each flooding event. This novel workflow produces temporally granular flood damage quantification which incorporates evolving hydrodynamic and meteorologic conditions. We hypothesize that wetland restoration will be cost-competitive with levee heightening once ecosystem services are financialized along with avoided flood losses.

How to cite: Zapp, S., Brand, M., Taofiq, Y., Bacopoulos, P., Diefenderfer, H., McKeon, M., Schmitt, J., and Janousek, C.: Economic comparison of sea-level rise adaptation solutions along the green-gray infrastructure continuum: a case study from an estuary on the U.S. Pacific Coast, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16049, https://doi.org/10.5194/egusphere-egu26-16049, 2026.

Saltmarshes provide numerous ecosystem services, contributing to climate change mitigation (carbon sequestration) and adaptation (coastal protection). While capable of accreting sediments in a dynamic equilibrium with changing sea levels, uncertainty remains regarding their continued resilience under accelerated rates of sea level rise (SLR). Ultimately, an improved understanding of how saltmarsh systems develop and evolve under changing conditions is needed to inform management and restoration strategies. Numerical frameworks that couple hydro-morphodynamics and vegetation dynamics (“eco-geomorphic” models) are emerging to support such advancements. Challenged by conflicts of scale and high computational costs, however, saltmarsh modelling studies often implement simplifications that ignore short-term vegetation dynamics such as seasonal growth cycles. Consequently, it remains poorly understood how seasonal variation impacts saltmarsh eco-geomorphic processes on sub-annual to multi-decadal timescales, and if there are implications for ecosystem vulnerability to SLR.

To address this, a numerical study was developed based on seasonal stem measurements of Sporobolus alterniflorus from the St. Lawrence Estuary (Québec, Canada). Coupling hydro-morphodynamics (TELEMAC-2D, GAIA) with a cellular automaton for vegetation dynamics, a novel eco-geomorphic framework was applied to simulate saltmarsh development under scenarios with explicit seasonal variation, versus vegetation properties averaged over the growing season. For each scenario, the model was used to simulate 180 years of eco-geomorphic development for an initially bare, idealized tidal domain.

This study demonstrates, for the first time, how sub-annual seasonal processes contribute to ecosystem development over the long-term (decades to centuries). Simulations that incorporated explicit seasonal variation in stem characteristics yielded more rapidly accreting saltmarsh platforms, with denser tidal channel networks; both supporting improved resilience under SLR. Sediment delivery to saltmarsh interiors was promoted during seasons of low biomass, while seasons of peak biomass strengthened flow routing around vegetation patches, enhancing channel network development. Identifying new mechanisms underlying long-term saltmarsh evolution and resilience, this work highlights the critical importance of integrating seasonality into eco-geomorphic models.

How to cite: Markov, A., Stolle, J., Temmerman, S., Gourgue, O., Nistor, I., and Pilechi, A.: Seasonal variation in stem morphology critically influences long-term saltmarsh development, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16146, https://doi.org/10.5194/egusphere-egu26-16146, 2026.

Saltmarsh habitat provides important ecosystem services such as water quality regulation, carbon sequestration, and flood defence. Marshes are also experiencing significant losses globally. One method of restoring saltmarsh habitat is the use of structures such as sedimentation fields to enclose areas of mudflat and encourage sediment deposition. Sedimentation fields offer opportunities for restoration in areas that are unsuitable for other, more common, restoration methods such as managed realignment. They can also provide protection for fixed engineered defence structures such as sea walls. However, sedimentation fields have predominantly been studied using numerical models or with a focus on vegetation colonisation. Therefore, it remains unknown whether the restored habitat can become self-sustaining through biophysical feedback processes accelerating vertical marsh buildup or whether there is a need for continued maintenance to prevent erosion of the deposited sediment.

This study presents findings from an empirical investigation of Rumney Great Wharf, Wales. Sedimentation fields were constructed here between 1989 and 2005, but since 2010 no maintenance has been carried out with fencing being eroded and lost. This allows for assessments of whether the restored area is self-sustaining or if continued maintenance is required. We show that 87% of the total area enclosed by sedimentation fields experienced erosion between May 2023 and 2024. This is despite sediment trap measurements indicating the potential for sediment to accrete at more than 9 cm/year. Trends in sedimentological processes are contextualised using depth, current velocity, wave action, and suspended sediment data. Our findings are evaluated in terms of the requirements for further research into sedimentary processes operating in sedimentation fields.

Using the insights gained from our study, we discuss the need to consider sedimentation fields as a continuation of human activity influencing natural processes, rather than the removal or reversal of the influence of prior human activity. We emphasise the need for transdisciplinary approaches to (i) develop further understanding of the interactions between physical and biological processes to enhance ecosystem functioning in sites restored using sedimentation fields, and (ii) to inform the design of future schemes. Further research is needed to fully justify the implementation of future sedimentation field construction, identify suitable locations for such schemes and inform their management, and to ensure such schemes provide a nature-based solution to coastal management challenges.

How to cite: Dale, J., Ladd, C., Kennedy, M., and Farrell, M.: Sedimentation fields: human activity, maintenance and the implications for successful saltmarsh restoration, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17431, https://doi.org/10.5194/egusphere-egu26-17431, 2026.

As climate change intensifies storm frequency and sea-level rise, global shorelines face increasing rates of erosion, threatening coastal ecosystems such as saltmarshes. Although saltmarshes are critical global assets for carbon sequestration and coastal defence, they are increasingly vulnerable to hydrodynamic stress. Conventional coastal engineering strategies to reduce erosion and maintain our coastal ecosystems often require significant capital and resource-intensive maintenance, driving an urgent need for lower-cost, nature-based solutions (NbS).  

Driftwood, or Large Woody Debris (LWD), is a naturally occurring resource that is frequently removed from many coastal systems, despite its ecological benefits. While the use of LWD for sediment stabilisation and dune restoration has been documented in areas of Canada and New Zealand, many projects continue to face high failure rates. A significant disconnect exists between high-level policy support for these NbS and the lack of technical guidelines to ensure their success. Consequently, the potential for anchored LWD to serve as a permanent intervention in saltmarsh environments remains under-researched.

This project seeks to address the current lack of technical guidelines and the high rate of previous project failures by investigating the viability of anchored LWD as an NbS and restoration strategy. By evaluating the impact of these structures on morphodynamics and sediment stability, this research aims to standardise the application of anchored LWD, offering a scalable, cost-effective strategy to utilise debris as coastal defence.

How to cite: Twomey, A. and Goseberg, N.: From debris to defence: reclaiming driftwood's role on our shores, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19931, https://doi.org/10.5194/egusphere-egu26-19931, 2026.

In response to the challenges posed by coastal erosion and rising sea levels, bio-inspired strucutres represent an innovative solution by combining physical protection with ecological benefits. This study investigates how key structural parameters, including tortuosity, surface roughness, porosity, and structural diversity, affect near-bed shear stress and turbulence around bio-inspired coastal defense modules.

Wave flume experiments were conducted using fifty-one different modules, organized in three rows and tested under five monochromatic wave conditions (heights 2.5–10 cm, periods 1–2 s), scaled for Mediterranean deployment. Measurements from resistive wave gauges and Vectrino velocimeters were used to analyse wave energy dissipation, vertical current profiles, turbulence, and bed shear stress.

Preliminary results show that structural geometry appears to influence local hydrodynamics, with implications for a better understanding of how the selected parameters affect the surrounding hydrodynamic conditions. The effects of the parameters are ranked to guide the development of efficient, multifunctional, bio-inspired coastal defense solutions. A combination of several of these parameters, within a single module and then at the scale of an entire structure, allowed us to explore the potential benefits of structural complexity in coastal protection systems.

How to cite: Martinot, M., Meulé, S., Certain, R., Cognat, M., Beudin, A., Dalle, J., and Caceres-Euse, A.: Influence of structural parameters of Coastal Protections on near-bed shear stress and turbulence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21266, https://doi.org/10.5194/egusphere-egu26-21266, 2026.

The Oxford Marine Protection Project, in collaboration with WWF Philippines, is supporting community-based mangrove conservation in the Del Carmen Mangrove Forest in Siargao, recognised as the largest intact mangrove forest in the Philippines. We present an integrated framework combining on-ground assessments with novel satellite and geospatial datasets across four categories: habitat extent and condition, environmental stressors, biodiversity indicators (quantified using Bio-in-the-Box pipelines), and spatialised threat data, including evidence of illegal logging.

This multi-source approach is used to assess ecosystem vulnerability and co-benefits such as coastal protection and blue-carbon potential. The framework supports the identification of biodiversity hotspots, storm-resilient areas, degraded zones requiring restoration, and locations impacted by resource extraction. Our work demonstrates how integrated remote sensing and biodiversity data can strengthen the design, prioritisation, and long-term evaluation of nature-based coastal solutions in community-managed mangrove systems.

How to cite: Mukherjee, H.: Mangrove conservation in the Largest Mangrove Forest of Philippines - Integrating satellite data with community conservation efforts , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21594, https://doi.org/10.5194/egusphere-egu26-21594, 2026.

For centuries the Sibillini Mountain Range, in the Italian Apennines, has been inhabited by mysterious legendary tales, celebrated by poems, romances, travel diaries and even scientific investigations. On the top of Mount Sibyl (2,173 mt.) the entrance to a large cave is present, now obstructed: according to the legend it housed the subterranean abode of an oracular Sibyl, a prophetess and seductive queen. Another legend lives on Mount Vettore (2,476 mt.), a different peak raising just a few miles away: there lies a glacial lake, in which the cursed body of Pontius Pilate, the ancient prefect of Judaea, would rest guarded by legions of demons. To them necromancers would have resorted, in past centuries, for the consecration of their grimoires.

Since the late eighteenth century, the two legends have been an object of study for philologists, medievalists, folklorists and other scholars. Research has mainly been conducted on the sibylline legend, considered as an independent tale, in search of a mythical connection to classical Sibyls. However, a correct approach to both legends should be based on the following question: how can the Sibillini Mountain Range host two different, mythically-mighty, mutually-independent legendary tales, on two neighboring peaks?

A new insight on the origin of this legendary tradition has been recently proposed by the author of the present abstract, based on a geomythological approach.

The applied methodology has included a phased analysis specifically designed to address the multi-layered stratification of the legendary material living amid the Sibillini Mountain Range.

The results of the first phase rendered it possible to outline the manifest lineage of the legend of Mount Sibyl from the Matter of Britain, in which a similar character named 'Sibyl' is widely present as a companion and alter ego of Morgan le Fay; at the same time, the well-known medieval origin of the legend of Pontius Pilate and his corpse was fully retraced: a tale that has been narrated in a long series of works since the High Middle Ages, showing that the legend of the Sibillini Mountain Range is the local version of a wider tradition.

The subsequent analysis has cast a specific light on the potential presence of an earlier legendary tradition, marked by a dark hue and significant otherworldly characters. This more ancient narrative was certainly a main attraction factor for the later, medieval legends.

Finally, it clearly appeared that the cave and the lake were fundamental elements in the original, underlying legend, as geographical landmarks and possible access points to some sort of Otherworld in the beliefs of the local populations in antiquity.

As a conclusion, the original legend was conjecturally connected with the peculiar seismic behaviour of the Sibillini Mountain Range, whose territory is recurrently stricken by devastating earthquakes (2016, 1979, 1859, 1730, 1703, 1328, 99 B.C., 268 B.C. and beyond). The presence of a cult of earthquake demons to be appeased was envisaged. This is an unprecedented result, never proposed before by other scholars: a bright instance of mythogenic landscapes, cultural narratives and intangible geoheritage.

How to cite: Sanvico, M.: The Sibillini Mountain Range in Italy: a Disregarded Geoheritage now Unveiled, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2327, https://doi.org/10.5194/egusphere-egu26-2327, 2026.

The 1755 Lisbon earthquake was one of the most powerful and destructive earthquakes in European history. It struck on the morning of All Saints Day around 09:40 local time, with an estimated magnitude of 8 to 9 Mw. The initial violent shaking for 3 to 9 minutes, was followed by a Tsunami 1 hour later.  In Lisbon the height of the tsunami waves is estimated around 5 to 6 meters, but in several coastal areas it may have attained over 15 meters. The disaster destroyed the powerful city of Lisbon and had a profound effect on the European Enlightenment, sparking intense philosophical and theological debates about divine judgment, the problem of evil (theodicy), and human rationality.

The higher historical record of the tsunami has been reported at Penafirme, a small locality at the Oeste Geopark, 50 km N of Lisbon. Detailed written descriptions testify the tsunami advance and the destruction of an Augustinian Order convent at the height of 16m and 700m away from the coastline. Around this place, several myths appeared, related to this geodynamic event.

i) Santa Cruz (Holly Cross) – when the fishermen saw the huge wave coming from the sea, they ran away to embrace and stay all together around a big wooden cross, which miraculously saved them.

ii) Frei Aleixo (Friar Alexis) – considered to be the only victim, this monk tried to escape the tsunami, running uphill over 80m, and dying due to exhaustion at the top, where a limestone cross signs the fatality.

iii) Ilhéu Grande (Big islet) – a small islet once existed close to the convent and local people say that the tsunami brought so much sand that it connected it to land.

iii) Quinta da Areia (Sandy Farm) - the sea surged and stopped near this rich coastal farm and two mermaids were dragged ashore; the farm workers burned the younger mermaid and the mother mermaid told them they would never have luck again, up to the fifth generation; the farm quickly declined and has been abandoned, remaining in ruins until today.

All these local stories and myths testify the importance given by local people to remarkable natural hazards, such as a huge tsunami. These myths and the historical importance of the event and the ruins are a vivid reminder of the importance of geodynamic processes in shaping the landscape and the communities’ traditions at the Oeste UNESCO Global Geopark.

How to cite: Pimentel, N.: Local myths related to the 1755 Tsunami at Penafirme (Oeste Geopark, Portugal), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5984, https://doi.org/10.5194/egusphere-egu26-5984, 2026.

Many human communities across the globe have associated seismic activity and ground motion with mythological creatures believed to roam beneath the Earth’s surface. A recurrent expression of this association is the link between snakes and earthquakes in human folklore. In the Americas, the Chumash people of southern California attributed the frequent ground shaking along the San Andreas Fault to the movements of underground serpents. In Patagonia, the struggle between the snakes Trentren and Caicai occupies a central place in Mapuche mythology, embodying tectonic uplifts and subsidence associated with subduction earthquakes. In the central Andes, the amaru, a chthonian, serpent-like deity of pre-Hispanic cosmology, was likewise associated with violent geological or climatic processes, and its appearance was commonly perceived as a rupture in the equilibrium of the world, a pachacuti. In ancient and modern Peru, earthquakes have repeatedly reshaped landscapes and profoundly affected human societies. In the absence of an intelligible pre-Hispanic writing system, indigenous oral traditions, later recorded in colonial chronicles, represent a particularly valuable, yet long underexploited, source for identifying past extreme natural events. These transgenerational memories are nonetheless rooted in empirical environmental knowledge, conveyed through alternative narrative systems.

This contribution proposes a geomythological reinterpretation of a passage from the Relación de antigüedades deste reyno del Piru, written in the mid-seventeenth century by the indigenous author Pachacuti Yamqui Salcamaygua. The chronicle recounts the seemingly fantastic appearance of an amaru above the city of Cusco during the Inca period. Through a cross-analysis of toponymic, geomorphological, and seismological data, we suggest that the underlying event corresponds to a major earthquake during the 15^th century CE. The propagation of a surface rupture across the landscape may have been perceived as the sudden emergence of a serpent-like being wriggling over the mountains and leaving an undulating surface trace. If confirmed, this account may represent the oldest seismic event documented by written sources in South America. More broadly, this oral tradition may testify to the strong imprint of earthquakes on the collective memory of Andean societies by transforming a tectonic feature into a mythogenic landscape. Beyond its scientific implications, this geomyth also holds significant potential in terms of geoheritage and geoeducation. Within the framework of a French–Peruvian initiative, this cultural narrative has been adapted into an illustrated book to raise awareness of seismic risk among younger generations.

How to cite: Combey, A., Audin, L., and Benavente, C.: When Faults Wriggle.  Geomythological Evidence of a Pre-Hispanic Earthquake in Cusco, Peru, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7009, https://doi.org/10.5194/egusphere-egu26-7009, 2026.

Mythogenic landscapes are environments where geological features and physical processes actively shape myths, beliefs, and cultural imaginaries. This contribution explores the role of mineral-specific physical properties—particularly those of quartz and tourmaline—in the development of symbolic narratives, ritual practices, and geomyths associated with prehistoric landscapes. Quartz and tourmaline are widely documented in archaeological contexts worldwide, including rock art sites, ritual deposits, burials, and ceremonial spaces, suggesting that their cultural significance extends beyond purely utilitarian uses.

Both minerals exhibit remarkable electrical and luminous behaviors. Tourmaline displays strong piezoelectric and pyroelectric properties, generating electric fields, particle attraction, and ash reorientation when subjected to pressure or heat. Quartz, in addition to being piezoelectric, exhibits triboluminescence: the emission of visible light when fractured, struck, or knapped. These effects can produce sparks, flashes, and electrostatic phenomena that are directly observable without specialized technology. In prehistoric contexts—during tool production, rock engraving, or campfire activities—such phenomena may have been perceived as manifestations of vital or solar forces acting within stone.

Ethnographic, linguistic, and archaeological evidence indicates that quartz has been interpreted in several cultures as a “solar stone,” a material associated with light, power, and cosmological significance. The recurrent presence of quartz in ritual and symbolic contexts suggests that its luminous and electrical responses contributed to its mythogenic potential. Similar interpretations can be proposed for tourmaline, whose pyroelectric behavior is reflected in vernacular names such as ash-attractor, pointing to empirical observations of its interaction with fine particles.

This paper argues that these minerals acted as abiotic cultural agents within mythogenic landscapes, mediating between geological processes and human perception. Their physical properties may have inspired solar motifs in rock art, geomyths explaining landscape features, and beliefs linking stone, light, and spiritual power. Such interpretations highlight how geophysical phenomena contributed to intangible geoheritage long before scientific explanations emerged.

By integrating mineral physics, archaeology, and geomythology, this study emphasizes the need to evaluate geoheritage not only for its scientific value but also for its culture-shaping significance. Recognizing the mythogenic role of quartz- and tourmaline-rich landscapes enhances their potential for geoeducation, public engagement, and geotourism, reinforcing the deep and enduring connections between humans and the dynamic Earth.

This publication is part of the grant RYC2023-042760-I, funded by MCIU/AEI/10.13039/501100011033 and ESF+.

How to cite: Freire-Lista, D. M. and MacCoy, M.: Quartz and Tourmaline: Light, Electricity, and the Geophysical Roots of Mythogenic Landscapes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7929, https://doi.org/10.5194/egusphere-egu26-7929, 2026.

The association of supernatural imagery with elements of the landscape was a common phenomenon in traditional cultures (Piotrowski 2024; Juśkiewicz et al. 2025). This process depends on the cultural context and encompasses two fundamental levels of the relationship between the abiotic environment and humans: symbolic interaction or/and utilitarian interaction. Symbolic interactions shaped the perception and meaning of erratic boulders. Legends (belief narratives) – similar to myths – link the existence of geological objects with the actions of supernatural forces, such as devils or mythically inclined figures, e.g., giants (Motz 1982, 70-71; Lanza, Negrete 2007, 61). Examples of such correlations can be found in Kashubian folk beliefs, where peninsulas were said to have been created by giants known as Stolem (Gulgowski 1911, 169).  In Pomerania, legends associate glacial erratics with both mythological beings (for example giants and devils) and historical figures (Huns, Teutonic Knights, Swedes), who rise to the rank of mythical heroes (Kolberg 1965, 375; Lorentz 2020, 148). Similar phenomena can be observed in other regions of Europe, such as Scandinavia, where rocks and stones were often attributed to the activities of trolls and giants or heroes in England (Oinas 1976, 6-7). A significant number of boulders bear traces of human processing, such as incisions and chisel marks, aimed at breaking the rock or producing millstones. These activities had both functional and symbolic dimensions. Glacial erratics and all forms of human activity associated with them should be regarded as part of geocultural heritage, encompassing both material and immaterial aspects. Their value lies at the intersection of geology and culture. Such an approach reveals their multidimensional semiotic nature. Integrated into the processes of meaning-making and valuation – typical of human world-ordering – they generate representations characteristic of a given culture and historical period. Recognizing glacial erratics as geocultural heritage thus allows us to link natural and cultural landscapes, highlighting their role as tangible markers of human interaction with the environment across time.

Acknowledgements

This paper was conducted as part of two research projects funded by the National Science Centre in Poland (grant No. 023/49/N/HS3/02181 and grant No. 2019/35/B/HS3/03933)

References

Juśkiewicz, W.; Jaszewski, J.; Brykała, D.; Piotrowski, R.; Juśkiewicz, K. B.; Alexander, K.M., 2025. Supernatural beings of Pomerania: postmodern mapping of folkloristic sources. Journal of Maps 21(1). DOI: 10.1080/17445647.2024.2434015

Kolberg, O. 1965. Pomorze, t. 39, Wrocław-Poznań.

Lanza, T.; Negrete A. 2007. From myth to Earth education and science communication. In: Myth and Geology, eds. L. Piccardi and W. B. Masse. Geological Society. Special Publication 273: 61-66.

Lorentz F. 2020. Zarys etnografii kaszubskiej. In: Lorentz F.; Fischer A. Zarys etnografii Kaszub. Gdynia.

Motz, L. 1982. Giants in Folklore and Mythology: A New Approach. Folklore 93(1): 70-84.

Oinas, F.J. 1976. The Finnish and Estonian folk epic. Journal of Baltic Studies 7(1): 1-12.

Piotrowski, R. & Juśkiewicz, W. 2024. Folk Narratives about Water Bodies in the Southern Baltic Lowland: From Geomythological Interpretations to Examples of Symbolic Eco-Symbiosis. Folklore 135(4):534-552. DOI: 10.1080/0015587X.2024.2410055

How to cite: Piotrowski, R., Brykała, D., and Czubla, P.: Giants, Huns, and the Devil: Geofolklore of Erratic Boulders in the Southern Baltic Lowlands and Their Geocultural Significance, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10470, https://doi.org/10.5194/egusphere-egu26-10470, 2026.

Until the early 20th century, the economy operated in a nearly zero-waste manner, where tools and utensils were utilized until they were completely worn out and subsequently repurposed. A prime example of this historical circular economy is the reuse of millstones and quernstones. On the Southern Baltic Lowlands, these objects were often crafted in situ from Pleistocene erratic boulders transported by the Scandinavian ice sheet. Due to their high production costs and durable material, worn-out stones were rarely discarded; instead, they were adapted for new, often symbolic or structural roles.

Beyond their primary function in food production, these stones developed a specific emotional and cultural bond with human communities. In folklore and biblical tradition, the millstone became a powerful symbol of transformation, death, and rebirth. This spiritual dimension is reflected in their widespread use in sacred and funerary contexts. Millstones were commonly repurposed as altars, ciboria, and gravestones in both Christian and Jewish cemeteries. A unique regional phenomenon, particularly prevalent in Northern Poland and Northeastern Germany, was the practice of embedding millstones into the exterior walls of churches, where they served both as construction material and objects of local symbolic significance.

Structurally, the mass and pre-existing axial holes of these stones made them ideal for stabilizing monuments. Historical and archaeological evidence points to their use as foundations and socket-stones for high crosses. In these cases, the stones provided a ready-made anchorage system for large stone or wooden shafts.

In the modern era, these artifacts have transitioned into the realm of geotourism and geoeducation. Often featured in lapidaries or integrated into the small architecture of public parks and private gardens, they continue to document the enduring relationship between human creativity and geological resources. This long-standing practice of stone reuse demonstrates an early mastery of sustainable material management and remains a vital part of our geocultural heritage.

This work was supported by the National Science Centre, Poland (Grant No. 2019/35/B/HS3/03933).

How to cite: Brykała, D., Czubla, P., Piotrowski, R., Bartz, W., and Juschus, O.: Secondary Use of Millstones and Quernstones as an Example of Historical Circular Economy and Geocultural Heritage, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10700, https://doi.org/10.5194/egusphere-egu26-10700, 2026.

Dante’s Inferno has been profitably examined in geological terms. Although the landscape traversed by Dante and Virgil springs primarily from the poet’s imagination, it also contains numerous real-world geological events such as earthquakes and landslides. The poet’s Hell is also highly mythologized with copious references to classical myths, since biblical sources say little about the actual features of Hell. This poster builds on geological studies of the poem by considering the geophysical elements of Satan’s fall from Heaven, an event touched on in Jewish and Christian scriptures and paralleled somewhat by the Greek myth of the Titanomachy. Although Dante was not a scientist, he was one of the first persons in history to think through the physical effects of a large mass slamming into the earth at high speed. In Dante’s vision, the devil’s size and velocity are such that when he lands, he instantly creates Hell, a massive, circular, terraced crater that reaches to the center of the earth. This poster will place Dante’s medieval understanding of the physics of this event into conversation with meteoritics and the scientific understanding of impacts such as the K-T event, which destroyed most of the non-avian dinosaurs, and the moon’s possible formation that resulted when a Mars-sized planet (named Theia) collided with the early earth. The modern study of meteors was not firmly established until the 19^th century; prior to this point, meteors were seen as merely atmospheric phenomena, and were not connected to rocks falling from the sky. Only after scientific study of the 1833 meteor shower (known today as the Leonids and re-occurring about every 33 years, in the constellation Leo), did astronomers realize that meteors were astronomical events. Dante’s poetic anticipation of some of the insights of meteoritics thus confirms the Inferno as a mythogenic landscape and presents numerous opportunities for geo-education.  

How to cite: Burbery, T.: Meteoritics and Dante's Inferno: Examining Satan's Fall as an Impact Event , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14300, https://doi.org/10.5194/egusphere-egu26-14300, 2026.

Leigh Franks ORCID 0000-0003-1817-9769

Patrick D Nunn ORCID 0000-0002-3718-614X

Adrian McCallum ORCID 0000-0001-9295-5741

Abstract 

Australian Indigenous Oral Traditions preserve transgenerational memories of geological (and other environmental) events, including hazardous volcanic activity. Details within these recollections are increasingly being recognised for their potential to inform geoscientists and ethnographers about deep-time landscape evolution and related geological processes. Many traditions recall impactful events that changed or created particular landscape features that are well remembered in Indigenous narratives and are plausibly linked to identified locations. Such stories (or ‘geomythologies’) also may include eye-witness accounts of sea-level rise, meteor impacts, tsunami, earthquakes and volcanic eruptions, in some cases dating from the Early Holocene (11.7 ka BP) and possibly earlier. Despite enduring memories of eruptive events in Australia, not all volcanism has associated stories, raising questions about the reasons for why some stories may have survived and others did not.

This paper builds on global research into the longevity and accuracy of oral traditions and argues that Australian Aboriginal traditions of volcanism include some of the oldest such narratives of their kind in the world. It also demonstrates how efforts to ‘authenticate’ them (from Western literate-scientific perspectives) can provide a pathway for integrating Indigenous knowledge and academic scientific approaches. This study examines the presence and absence of oral traditions across mapped volcanic provinces and identifies a correlation between story occurrence and areas of geologically recent activity. It also finds a consistent absence of such traditions where eruptive activity is known to predate archaeologically constrained human occupation of the region.

How to cite: Franks, L., Nunn, P., and McCallum, A.: Australian Aboriginal Traditions of volcanism: Ancient recollections of eruptions and their nature, purpose, and contemporary importance., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15309, https://doi.org/10.5194/egusphere-egu26-15309, 2026.

Erratic boulders are among the most striking geological features left behind by former ice sheets. In Poland, repeated advances and retreats of the Fennoscandian Ice Sheet (FIS) during the Pleistocene resulted in the deposition of thick sequences of clastic sediments and fragments of Scandinavian bedrock of varying sizes, including large erratic boulders. These impressive geological objects are not only valuable archives of past glacial activity, but also play an important role in society, functioning as natural resources, prominent landscape markers, and rich sources of geomythological narratives.

This study examines the distribution and characteristics of large erratic boulders in Poland. These features were identified using published literature, maps, and catalogues of environmentally protected sites, such as registers of natural monuments. A comprehensive GIS database was compiled, incorporating all available information on each boulder, including location, dimensions, petrography, and, where possible, historical background. Many of these erratics possess considerable cultural significance for local communities, giving rise to legends and myths, serving as esoteric or symbolic places, or commemorating important historical events. This contribution presents and discusses the most compelling legends and myths associated with large erratic boulders in Poland.

This research was supported by the National Science Centre, Poland (grant numbers 2023/49/N/HS3/02181 and 2022/46/E/ST10/00074).

How to cite: Tylmann, K.: Great Glacial Giants: Erratic Boulders in Poland as Sources of Geomythology, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16628, https://doi.org/10.5194/egusphere-egu26-16628, 2026.

By mapping folklore narratives of the “supernatural” and ritual activities onto the landscape, interdisciplinary research demonstrates that village and estate boundaries embody liminal symbolism, marking thresholds between the “world of the living” and the beyond. Oral traditions concerning apparitions, sacrifices, burials, deaths, and the killing of folkloric beings are particularly concentrated along cadastral and estate boundaries, endowing them with a “supernatural” dimension and preserving traces of Slavic cultic spaces. Interdisciplinary analysis combining folkloristics, anthropology, archaeology, and geodesy further reveals that many old landscape boundaries were marked by Slavic and Christian sacred sites. Historical records and ethnological research also indicate that landscape boundaries were connected with a variety of ritual activities, one of the most interesting being “death resting places.” Several mythical mountains in the landscape of the Slovenian Karst function not only as boundary markers but also as cosmogonic mountains, threatening people with floods from within. Such is the case of the hill named Čuk, where a serpent or devil was believed to control the water inside the hill, and ritual processions were organized to protect the villages below from flooding. Another cosmic mountain is Nanos, which was believed to stand on pillars, and if they were to collapse, the region would be flooded. Drawing on these and similar oral traditions related to specific landscape features, the paper reflects on the meanings that such flood-threatening mountains held in traditional culture.

How to cite: Hrobat Virloget, K.: Mythological landscape of Karst, Slovenia. From the symbolism of boundaries to mountains floods. , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22259, https://doi.org/10.5194/egusphere-egu26-22259, 2026.

The contribution approaches early navigation and geography from a historical and interdisciplinary perspective, focusing on the role of the sky as a central reference system for spatial orientation, knowledge transmission and geographic thinking. Examining the Sumerian invention of constellations as "paths" and Isaac Newton's guessings about the sense of ancient Greek constellation design as practical and symbolic tools for navigation, the paper highlights how geographic knowledge was structured and preserved prior to the emergence of standardized cartography. Based upon examples from antiquity, the presentation situates early geographic practices within their cultural and scientific contexts and addresses the close relationship between astronomy and geography in the formation of early geoscientific thinking. The contribution is intended for an interdisciplinary audience and aims to stimulate discussion on the historical foundations of spatial knowledge and navigation.

How to cite: Wirth, K. and Buchroithner, M. F.: Heaven and Earth –How Early Geoscientists Inscribed Terrestrial Routes into the Sky, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22418, https://doi.org/10.5194/egusphere-egu26-22418, 2026.

The May 2019 tornado outbreak in south-central Chile abruptly reinserted tornadoes and waterspouts into public awareness, surprising both the population and parts of the atmospheric-science community. Yet historical sources indicate that these phenomena are not new in Chile, and Mapuche oral traditions preserve long-standing interpretations and practical orientations toward severe storms. Here we develop a situated geomythology framework to examine Mapuche narratives concerning the mewlen/meulén (tornado/whirlwind beings) as forms of situated knowledge (inarrumen) produced in specific territories and transmitted through oral, ritual, linguistic, and toponymic practices. Rather than reducing myth to a distorted chronicle that must be validated by a single "true" geophysical event, we analyze how narratives generate () observational resonances with physical processes and (ii) relational efficacy that guides action, memory, and care within communities. Drawing on colonial and republican written records (including early literary mentions), ethnographic archives, and contemporary references, we identify recurring descriptions of tornado behavior — cyclonic rotation, preferred approach directions, afternoon timing, and gradations of intensity — that are consistent with modern meteorological characterizations of tornadic convection. We further show that place names and vernacular uses of mewlen/meulén variants function as landscape-anchored markers of hazard memory and local prudential norms.

We argue that periods of institutional skepticism regarding tornado occurrence in Chile contributed to scarce systematic observations and delayed risk awareness, particularly in territories historically inhabited by Mapuche communities. Integrating historical–cultural evidence with meteorological perspectives can strengthen tornado climatologies in data-sparse regions and support risk communication that respects epistemic plurality while improving preparedness for rare but high-impact convective hazards.

How to cite: Rondanelli, R., Bastías-Curivil, C., Silva, M. I., and Charrier, R.: Mewlen, tornadoes and waterspouts in Chile: a situated geomythological perspective , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22790, https://doi.org/10.5194/egusphere-egu26-22790, 2026.

Rivers, deltas and coasts have dynamic patterns of sand, mud and vegetation. These patterns are colourful, energetic, alive, important to, and affected by, societies on Earth. In contrast, the remains of rivers and deltas on planet Mars tell a story of a dry, frozen and probably lifeless planet. For meaningful research, not only novel scientific methods are needed, but also the concepts enabling ourselves and our students to enhance our learning and societal application. We must and can do better in closing the circle between science, diversifying impact activities and educating the students. Our alumni could accomplish so much more if only they knew how.

Replicating and studying the dynamic patterns of river meandering and shallow estuaries in scale experiments (in my tidal flume www.uu.nl/metronome) has been challenging, not only because of the usual scaling problems. Representing such systems in scale experiments requires that we include a minimum set of processes and dynamic boundary conditions that allow a (quasi-)steady state to develop with the target patterns and behaviours. I will show how a complex biogeomorphic systems approach led to beautiful dynamic meandering rivers and estuaries in our lab. Our scale experiments play an unexpectedly large role in education and impact in showing tangibly how the rivers, estuaries and coastal plains developed and what this may mean for their management.

I will then take a step back and critically question what and how we are learning as experimenters and modellers. I learned about how we learn and how we can improve our learning and teaching by using concepts from philosophy of science on causality in complex systems, material modelling and representation of the world. I will focus on some academic thinking skills and societal literacy skills that are often underemphasized in education but fundamental to 21st century geomorphology with societal impact.

Third, societal use of, and interactions with, biogeomorphic systems pose challenges: the combination of accelerating climate crisis, historic land use change and intensifying economic activities deteriorate ecosystems and increase droughts, flooding and land loss. Ideally, societal responses to the climate and biodiversity crises are based on systems understanding on a timescale of years to centuries. Many scientists are hampered by taking either an activist position or an ‘objective’ or at least ‘neutral’ academic position, while there are 50 shades of green in between them. Merely ‘neutrally’ informing public and policymakers, as a sender, is ineffective because they, the receivers, have interests, perspectives and usually a lack of academic knowledge. Being an activist is also not often effective and may raise questions about the legitimacy of our science. How do we navigate these roles? I will show how I, in transdisciplinary teamwork, am learning to navigate the positionality of ‘neutral scientist’, educator, agent of change and political lobbyist, boldly stumbling where others have stumbled before.

How to cite: Kleinhans, M.: Concepts to close the circle between 21st century biogeomorphology, higher education and societal impact, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3116, https://doi.org/10.5194/egusphere-egu26-3116, 2026.

Cryosphere-fed rivers drain glacier, snow, and permafrost landscapes and are characterized by glacial, nival, pluvial and mixed hydrological regimes. Such river systems originate from high-mountain areas and polar regions, and transport water, sediment, nutrients, and organic carbon downstream, underpinning the freshwater and coastal ecosystems and supporting the lives of more than one-third of the world's population. In response to the amplified climate change, accelerating glacier-snow melt and permafrost thaw, the cryosphere-fed rivers are overall becoming warmer, wider and muddier associated with markedly increasing river turbidity and suspended sediment concentrations. In this talk, I will present the observed and modelled changes in cryosphere-fed rivers and examine their implications for channel mobility and the carbon cycle across both High Mountain Asia and the pan-Arctic. To better assess the impacts of changing climate on the functions and services of river ecosystems in strategically important cold regions, I highlight the pressing need to integrate multiple-sourced river observations, to develop empirical, physics-based, and AI-based river flux models, and to promote interdisciplinary scientific collaboration. The innovative system approach would best come from the creation of an interdisciplinary collaborative initiative, where geomorphologists, climatologists, ecologists, glaciologists, permafrost scientists, hydrologists, and civil engineers work together to establish an integrated cryosphere-water-sediment-carbon-ecology observation platform that facilitates the mechanism understanding and development of novel and powerful models. Furthermore, dialogues and collaboration between international scientists, stakeholders, local communities, and policymakers would help to bridge the gaps between state-of-the-art scientific findings and practicable adaptation strategies.

How to cite: Li, D.: Cryosphere-fed rivers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2198, https://doi.org/10.5194/egusphere-egu26-2198, 2026.

The hydrological response of a basin is fundamentally controlled by geomorphic processes, structures, and physiographic characteristics. Horton’s geomorphological laws, basin topology, and kinematic properties have long been employed to derive flood response in ungauged basins through various Geomorphological Instantaneous Unit Hydrograph (GIUH) frameworks. This study investigates ten ungauged tributary sub-basins of the Shilabati River in eastern India to analyse how basin morphometry and topology regulate travel-time distribution of water particles and flash-flood potential. The Width Function Instantaneous Unit Hydrograph (WFIUH), a GIUH variant, is applied to derive the geomorphological control on peak flow and time to peak, while the morphometric analysis is performed to investigate the effect of basin characteristics on these hydrologic response parameters. The WFIUH is obtained using the flow length extracted from the SRTM DEM, together with spatially variable and fixed hillslope velocities estimated from land use-land cover and slope using the Soil Conservation Services (SCS), uniform-flow, and Manning’s velocity formulae. Due to the absence of observed streamflow, WFIUH results are evaluated against the Geomorpho-climatic Instantaneous Unit Hydrograph (GcIUH) derived from climate-dependent channel velocity and drainage network topology, as well as observed flood events. 
Results show that all variable-velocity WFIUHs have longer time bases and a lower peak flow than fixed-velocity WFIUHs, because the highest velocity cells are associated with the smallest drainage contributing areas. The SCS-based variable velocity WFIUH aligns with the GcIUH, reproducing both the peak flow and time to peak of the IUH more accurately compared to the other methods. Small, circular, and comparatively steeper sub-basins exhibit shorter times to peak (8.5-10.5 hours), indicating a high flash-flood potential, mainly in sub-basins 3-6. On the contrary, elongated and well-bifurcated sub-basins reveal slightly delayed peaks (10.5-15.5 h) but remain capable of producing moderate-to-high floods due to their larger drainage areas, as confirmed by the flash flood event in 2025 in sub-basins 1, 8-10. Correlation analysis reveals that circularity ratio, relief ratio, and hypsometric integral are positively associated with peak flow, suggesting enhanced flow synchronization in compact and steep sub-basins. In contrast, time to peak shows moderate to strong negative correlations with these parameters and positive correlations with stream length and bifurcation ratios, indicating delayed response in elongated and highly branched drainage networks due to dispersed flow paths.
Therefore, basin morphometry and drainage network topology effectively govern hydrologic responses of the sub-basins. The spatially variable SCS velocity-based WFIUH provides a more realistic depiction of hydrologic response in ungauged sub-basins. Hence, this method is well-suited for event-based lumped hydrological modelling as well as for sub-basin prioritization in flash flood risk assessment.

How to cite: Das, T. and Das, S.: Geomorphic controls on flood response using the Width Function Instantaneous Unit Hydrograph framework , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-570, https://doi.org/10.5194/egusphere-egu26-570, 2026.

Coastal protection infrastructures such as rubble-mound breakwaters (RMBs) demand frequent geometric inspection to quantify armor-layer dynamics and support reproducible structural monitoring. While UAV-based photogrammetry and LiDAR are established reference techniques for rapid 3D mapping, high revisit rates remain operationally constrained by wind sensitivity, sensor payload limits, and regulatory flight restrictions. Videogrammetry complements these approaches by increasing inter-frame overlap and mitigating missed-trigger acquisitions, especially useful in complex coastal scenes (e.g., those affected by occlusions between armor units and block interstices). As in conventional photogrammetry, videogrammetry relies on image redundancy and self-calibration rather than highly sophisticated instrumentation. Despite this potential, consumer-grade action cameras remain scarcely validated for multi-epoch 3D monitoring in coastal engineering, mainly due to wide-angle lens distortion and coarse onboard GNSS geotag precision.

This study assesses pole-mounted GoPro videogrammetry for multi-temporal 3D relative change detection in the emerged portions of a detached rubble-mound breakwater at Cabedelo do Douro (PT). Two survey epochs were acquired in July 2024 and November 2024 to characterize the above-water zone, inspecting the seaward slope, the landward armor-toe transition, and the horizontal crest platform segment at one of the heads of the RMB. Frames were extracted at 1 Hz and processed in Metashape using an SfM-MVS (Structure-from-Motion Multi-View Stereo) self-calibrating camera model. Multi-epoch point clouds were coregistered in CloudCompare with ICP (Iterative Closest Point) refinement over stable crest and toe areas, and 3D changes were quantified using M3C2 (Multiscale Model-to-Model Cloud Comparison), generating signed distance maps and detection histograms. A concurrent UAV-RTK survey, supported by additional GNSS-measured ground control points (GCPs), served as a geometric benchmark.

Mean ActionCam-to-UAV sensor offsets were +0.06 m, confirming that, despite potentially unstable absolute georeferencing in GoPro-derived reconstructions, the resulting point clouds preserve sufficient geometric and scale consistency to support relative multi-temporal 3D change detection and the identification of concrete armor-unit displacements. Results confirm that pole-mounted videogrammetry supports rapid, repeatable, low-cost SHM (Structural Health Monitoring) observations, providing defensible detection thresholds and reproducible change-detection limits for engineering interpretation and maintenance support.

How to cite: Martínez Olmedo, V., Bento, A. M., Arza-García, M., and Gonçalves, J. A.: Feasibility of Action Camera-Based Videogrammetry for Multi-Temporal 3D Monitoring of Rubble-Mound Breakwaters, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2250, https://doi.org/10.5194/egusphere-egu26-2250, 2026.

Quick clays are fine-grained, highly sensitive marine deposits that are widespread across formerly glaciated regions, including Norway, Sweden, Finland, and Canada. The low remoulded strength of the quick clays makes them particularly susceptible to extensive retrogressive landslides, which pose serious challenges to society. Erosion is recognized as one of the most important pre-conditioning and triggering factor for quick clay landslide. Therefore, identification of the erosion hotspots is essential for understanding landslide initiation processes and for effective hazard mitigation in quick clay terrains. Machine learning has emerged as an effective tool for erosion hotspot mapping, allowing complex spatial patterns and nonlinear interactions among erosion-controlling factors to be identified from remote sensing–derived data. Recent studies have demonstrated that Deep Neural Networks can be effectively employed to identify erosion-prone zones in quick clay environments when sufficient labelled data are available. This study investigates whether unsupervised machine learning applied to remote sensing–derived data can effectively identify erosion hotspots in quick clay areas. A fully automated, Python-based workflow was developed for erosion hotspot mapping in quick clay areas using remote sensing–derived data. The dataset includes terrain, hydrological, environmental, and anthropogenic parameters relevant to erosion and slope instability. Initially, a total of twenty input parameters were considered. Pearson correlation coefficients were computed to assess inter-feature dependencies, and principal component analysis (PCA) was employed to evaluate feature importance. The unsupervised analysis was performed using multiple clustering techniques to capture different structural characteristics of the data where each cluster represents a distinct level of erosion susceptibility. The results suggest that the proposed unsupervised framework can effectively delineate erosion hotspots in quick clay areas and constitutes an initial step toward the development of early warning systems.
Acknowledgements
This work was supported by the Research Council of Norway through the SAFERCLAY project (Grant No. 352887). Orkun Türe was supported by the Council of Higher Education of Türkiye under the DOSAP scholarship programme and served as a visiting researcher at NGI and NTNU.

How to cite: Türe, O., Tao, R., L’Heureux, J.-S., Oguz, E. A., and Tyagi, A.: Fully Automated Unsupervised Machine Learning Framework for Mapping Erosion Hotspots in Quick Clay Areas Using Remote Sensing–Derived Data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5775, https://doi.org/10.5194/egusphere-egu26-5775, 2026.

The size and mobility of landslides control their impact on both landscapes and communities. Despite their importance to understanding landslide mechanisms and associated hazards, few studies have examined the factors controlling these two characteristics, particularly at a large scale. This is especially the case for deep-seated landslides that occur across diverse geomorphological and lithological settings. Further, most research focuses on recent landslides and thus fail to consider historical processes that could be associated with environmental conditions that differ from the contemporary ones. Here, we investigate the influence of geomorphology and lithology on the size and mobility of old and recent deep-seated landslides in the North Tanganyika-Kivu Rift region in Africa, an under-researched mountainous environment located in the tropics. Based on a comprehensive inventory of ~2500 landslides, we show that mobility increases with size, especially for the old landslides. These old landslides are significantly larger than the recent ones, likely due to potential progressive landslide growth over time and  influenced by the region’s paleoseismic activity. The main controls on both the size and mobility of deep-seated landslides are lithology and, to a lesser extent, fluctuations in Lake Kivu’s level during the Holocene. Landscape rejuvenation by migrating knickpoints associated with rifting also plays a key role in determining landslide size: in rejuvenated landscapes, landslides tend to be larger than those in relict landscapes. The presence of these large landslides favours the development of smaller ones along their margins, reflecting the influence of path dependency on landslide occurrence and size. Our findings underscore the importance of considering the chronology of landslide occurrence and the long-term legacy of landscape evolution in shaping landslide characteristics.

How to cite: Mugaruka Bibentyo, T., Dille, A., Deijns, A., Nzolang, C., Dewaele, S., and Dewitte, O.: Controls on the size and mobility of deep-seated landslides in the North Tanganyika - Kivu Rift region, Africa, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5929, https://doi.org/10.5194/egusphere-egu26-5929, 2026.

Ephemeral mountain streams on the western Andean slopes remain dry most of the year, yet during intense rainfall events they generate short-lived flash floods with exceptionally high sediment transport capacity. This study investigates the hydraulic response of the upper Río Seco micro-basin (Huaycoloro catchment, Peru) under extreme rainfall scenarios, using a hydraulic–geomorphological framework that links surface hydrology with sediment mobility thresholds. Design discharges were estimated through IDF-based rainfall analysis and classical hydrological methods, while sectional hydraulic modelling using the Manning equation provided flow velocities and bed shear stresses along representative channel reaches. Results indicate mean velocities ranging from 2.4 to 3.4 m/s and shear stresses up to 215 Pa. These values exceed the critical shear stress of the coarse gravel bed by more than five times, indicating generalized sediment mobility and strong incision potential in confined steep reaches. Such conditions promote significant sediment supply from the upper basin, increasing the likelihood of downstream channel aggradation and flood hazard in peri-urban sectors of eastern Lima. To our knowledge, this is the first hydraulic–geomorphological quantification of sediment mobility thresholds in an arid Andean micro-basin under design-storm conditions. The findings provide quantitative evidence supporting the need to transition from purely water-based flood models toward sediment-inclusive risk assessments in steep ephemeral mountain catchments.

How to cite: Rosales Torres, L. and Cárdenas-Gaudry, M.: High-energy sediment dynamics in ephemeral Andean mountain streams: The case of Río Seco, Peru, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6006, https://doi.org/10.5194/egusphere-egu26-6006, 2026.

Flood-prone small mountainous catchments hosting critical infrastructure, such as bridges and transport networks, require integrated hydrologic–hydraulic analyses to ensure long-term resilience under changing climatic and land-use conditions. This study develops a coupled HEC-HMS–HEC-RAS modelling framework to quantify design discharges, inundation patterns and local hydraulic controls for the torrential stream crossing the settlement of Kato Nevrokopi in Northern Greece. Using high-resolution topographic data (DEM), GIS-based basin delineation and long-term rainfall records, design storms for multiple return periods are derived and transformed into flood hydrographs at the catchment outlet. These hydrographs force 1D steady-flow simulations in HEC-RAS, explicitly representing bridges, piers and local constrictions that act as morphodynamic bottlenecks and potential failure points under extreme flows. Model results are used to generate flood extent and water-depth maps for events up to the 1,000-year return period, identify critical cross-sections where afflux and backwater effects are most pronounced, and assess the effectiveness of alternative layout and channel-training configurations. The analysis is framed within the current EU Floods Directive 2007/60/EC and Greek legislation for stream delineation, linking quantitative hazard metrics to planning constraints and infrastructure design requirements. The work highlights how relatively simple, openly available tools, when combined with detailed geometric representation of bridges and channel morphology, can support evidence-based decisions on flood protection works, minimise over-engineering, and improve the adaptive management of critical infrastructure in steep, data-scarce basins.

How to cite: Pavlidis, K. and Valyrakis, M.: Hydrologic-hydraulic modelling and flood hazard mapping for infrastructure resilience in a small mountainous catchment on Northern Greece, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7986, https://doi.org/10.5194/egusphere-egu26-7986, 2026.

The construction of mega-canals necessitates a profound understanding of the pre-existing fluvial equilibrium to mitigate adverse geomorphic consequences, particularly in rivers with limited channel capacity. This study focuses on the intrinsic stability mechanisms of the Qin River, a typical small-to-medium-sized mountainous river in South China, prior to the implementation of the Pinglu Canal project. Field surveys and sediment analyses were conducted to characterise the natural bed state, with a focus on a morphologically representative reach. The findings indicate that the riverbed has historically maintained a strong dynamic equilibrium, supported by lateral confinement from riparian vegetation and natural armor processes unique to mountainous fluvial regimes, which are derived from tributary inputs. The analysis reveals that specific hydrodynamic thresholds and sediment connectivity are essential for maintaining this stability. Therefore, rather than hydraulic stress alone, the system's main vulnerability is determined to be the possible disruption of these established equilibrium conditions, particularly with regard to geological substrate constraints and longitudinal continuity. These results establish a scientific standard for assessing the potential disturbance risks of canalization in delicate mountainous river systems by providing a critical morphodynamic baseline.

How to cite: Zhu, S., Sun, J., Liu, C., Chen, L., and Chen, W.: Natural Riverbed Stability in a Small-to-Medium-Sized Mountainous River: A Baseline Investigation of the Qin River Prior to the Pinglu Canal Construction, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8868, https://doi.org/10.5194/egusphere-egu26-8868, 2026.

The traditional workflow in palynology begins with the removal of rock minerals through acid digestion and heavy liquid separation, followed by mounting the organic residue on a glass slide, and analysing it under a transmitted light microscope. Using the microscope, palynologists manually identify and assign the observed particles to predefined categories within a designated counting area on each slide. Counting typically continues until a target number of particles has been reached (often between 200 to 300).

Beyond the commonly analysed palynomorphs such as pollen, spores, and dinoflagellate cysts, palynological slides may also contain a diverse range of acid resistant organic sedimentary particles, including freshwater algae, phytoclasts, amorphous organic matter, and many others. Examining the full spectrum of these particles is known as palynofacies analysis. It is one of the most powerful methods for reconstructing depositional environments in sedimentary rocks, as it relies on the distribution and relative abundances of these particles.

However, traditional counting methods for palynological and palynofacies analysis present several limitations. The counting area is rarely defined with precision, making it difficult to reproduce analyses. As a result, if any annotations need to be corrected, the entire counting workflow must be repeated. A particularly challenging aspect is the objective estimation of particles such as amorphous organic matter or phytoclasts, which are always fragmented and do not exist as discrete entities. Moreover, identification accuracy can vary substantially between analysts depending on experience, introducing challenges for reproducibility, comparability, and integration across datasets.

Digitizing palynological slides offers a promising opportunity to reduce subjectivity and personal bias by enabling particle annotation directly on high resolution digital images. This approach also supports iterative analysis, allowing annotations to be updated or refined without repeating the microscopy workflow. Through the ArtPOP project, we aim to develop objective, widely applicable annotation tool that enhance the robustness of paleoenvironmental reconstructions and facilitate integration across diverse palynological datasets. In this presentation, we provide an overview of challenges and advantages associated with digitizing the palynological workflow. We also present our preliminary results of the AI-augmented annotation of selected sedimentary particles.

How to cite: Śliwińska, K. K. and Andrianov, N.: ArtPOP - Automated RecogniTion of Palynomorphs and Organic sedimentary Particles , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10337, https://doi.org/10.5194/egusphere-egu26-10337, 2026.

The Cretaceous–Paleogene (K/Pg) mass extinction represents one of the most severe crises in Earth history, with marked regional variations in the tempo of pre- and post-extinction environmental stress and ecological recovery. The Um Sohryngkew River (USR) section of Meghalaya (NE India) provides a unique perspective on stress and recovery dynamics in a marine setting proximal to the Deccan Traps. This study integrates planktonic foraminiferal assemblage data with sedimentological observations and bulk-carbonate δ¹³C measurements to reconstruct the nature and duration of marine stress and to constrain the timing of ecological and carbon-cycle recovery in the eastern Tethyan realm. This integrated, high-resolution multi-proxy approach was previously lacking for this Deccan-proximal archive, and provides a critical constraint on how volcanogenic forcing modulated K/Pg stress and recovery at regional to global scales.

The late Maastrichtian record at USR indicates highly stressed surface-ocean conditions. Planktonic assemblages are dominated by small opportunistic taxa, particularly Guembelitria cretacea (>80%), with strong dwarfing, dominance of thin-walled morphotypes, poor preservation, and a near absence of heavily calcified taxa (e.g., Pseudotextularia spp., Globotruncana spp.). These assemblage and preservation features point to sustained calcification stress and unfavourable conditions for carbonate production in surface waters, consistent with enhanced nutrient input and surface-water acidification under intensified continental weathering/runoff and volcanogenic CO₂ emissions. Following the K/Pg boundary, planktonic foraminiferal abundance (4 tests/g) and diversity remained markedly suppressed through the early Danian. The post-boundary interval is similarly characterised by persistent dominance of small opportunistic taxa (>30%; e.g., Guembelitria spp. and Chiloguembelina spp.) and continued dwarfing, indicating sustained calcification stress and hindered ecosystem rebuilding. Bulk-carbonate δ¹³C indicates delayed carbon-cycle recovery, beginning only after ~750 kyr at USR compared to ~200–300 kyr at many distal sites. Ecological recovery lagged further, with low diversity and small test sizes persisting for ~2 Myr until biozone P1c, indicating decoupling between carbon-cycle recovery and biological reorganization under continued environmental forcing.

The first robust evidence for ecological improvement appears in planktonic foraminiferal biozone P1c, where assemblages become more diverse and better preserved, test sizes increase, and morphogroup proportions stabilise. These changes suggest improved conditions for calcification, progressive strengthening of the pelagic carbonate system, and a more efficient biological pump. By biozones P1c–P2, community structure indicates that ecological balance was largely restored, and carbonate production increased steadily towards a better-developed carbonate-factory environment. Comparison with global K/Pg records suggests that recovery mechanisms in the USR section broadly mirror global ecological and biogeochemical feedbacks, but their timing is substantially delayed relative to distal sections. Importantly, similar evidence for prolonged stress and delayed recovery has also been documented from the Krishna–Godavari Basin of southern India, supporting a coherent regional pattern in marine environments proximal to the Deccan Traps. Together, these Deccan-proximal records highlight strong spatial heterogeneity in post-K/Pg recovery trajectories, including a delayed return to stable carbon cycling, carbonate production, and ecosystem structure.

How to cite: Patra, S., Punekar, J., Srivastava, P., Rawat, S., Bhadran, A., and Girishbai, D.: Delayed carbon-cycle stabilization and ecological recovery across the K/Pg boundary: evidence from the Um Sohryngkew River section, Meghalaya (India), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10713, https://doi.org/10.5194/egusphere-egu26-10713, 2026.


Incipient sediment motion in turbulent flows remains difficult to characterize and predict because the underlying hydrodynamic forces are highly intermittent and events are sparse in time, even in well-controlled experiments. This study investigates whether temporal deep-learning architectures can detect the onset of particle motion directly from high-frequency velocity time series measured by an instrumented “smart sphere” [1, 2], without explicit force or torque measurements. The workflow includes detrending and cleaning of raw signals, physics-informed signal transforms (e.g. smoothed velocity, acceleration, jerk, and kinematic impulse proxies), segmentation with sliding windows, and supervised training of temporal deep-learning architectures, including recurrent, convolutional, and attention-based models, using class-imbalance mitigation such as focal loss, class weighting, and data augmentation.
Hyperparameter optimization is performed automatically with Optuna, and model performance is assessed using ROC and precision–recall curves, confusion matrices and time-resolved prediction performance. Results show that all tested architectures can learn consistent kinematic signatures preceding incipient motion from single-axis velocity time series, with models incorporating attention mechanisms achieving the highest recall on rare motion-onset events, consistent with their ability to focus on intermittent, high-magnitude kinematic bursts preceding entrainment. These findings demonstrate that deep learning applied to smart-particle sensor data can provide an efficient, non-intrusive tool for particle-scale sediment transport monitoring and real-time–capable event detection. The approach is directly relevant to the session’s focus on particle-scale transport mechanics and data-driven upscaling, and opens avenues for integrating deep-learning-based event detection into multi-scale sediment transport models in geophysical and engineered flows.

References
[1] Al-Obaidi, K., Xu, Y., & Valyrakis, M. (2020). The design and calibration of instrumented particles for assessing water infrastructure hazards. Journal of Sensor and Actuator Networks, 9(3), 36.
[2] AlObaidi, K., & Valyrakis, M. (2021). Linking the explicit probability of entrainment of instrumented particles to flow hydrodynamics. Earth Surface Processes and Landforms, 46(12), 2448-2465.

How to cite: Mavris, I. and Valyrakis, M.: Rare-event detection of incipient sediment motion from smart-particle time series using deep learning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11678, https://doi.org/10.5194/egusphere-egu26-11678, 2026.

Understanding transformations of the climate system in the geological past is essential for predicting and mitigating the effects of global climate change in the next future. The geological record provides a unique archive that documents long-term fluctuations of environmental variables, including seasonality. Seasonality appears to have played a crucial role in extreme climate transitions, highlighting the importance of constraining its variability in the past. Increased seasonality is often associated with colder conditions and the development of ice accumulations, making it a key parameter for understanding and forecasting climate change.

Species of the brachiopod Gigantoproductus are giants within the Palaeozoic sedentary benthos, characterised by exceptional size and thick shells, reaching over 30 cm in width and more than 1 cm in shell thickness. These features make them unparalleled bioarchives for palaeoecological and palaeoclimatic reconstructions, enabling the investigation of long-term changes during key intervals of past climate change.

In this study, specimens of Gigantoproductus semiglobosus from upper Visean (Mississippian, Carboniferous) successions of western Ireland (Aran Islands and the Burren) were subjected to detailed diagenetic screening and subsequently analysed using a sclerochemical approach (δ¹⁸O, δ¹³C). These analyses were used to reconstruct seasonal variability and to provide additional evidence for the timing of Mississippian phases of the Late Palaeozoic Ice Age (LPIA).

Our results show that δ¹⁸O profiles from well-preserved shells record high seasonal variations (Δδ¹⁸O = 0.9 to 1.9 ‰ corresponding to a ΔT = 4 to 11 °C) for palaeoequatorial settings, as also observed in coeval species of Gigantoproductus from the UK (Angiolini et al., 2019). This seasonal variation is much higher than that recorded in comparable shallow water, low latitude environments both nowadays and in the distant past. The pronounced seasonality recorded by several species of Gigantoproductus from western Ireland and the UK at low palaeolatitudes supports the onset of a sustained Gondwanan glaciation in the late Visean. Also, the palaeogeographic distribution of the species of Gigantoproductus and the geochemical composition of their shells indicate that low-latitude Mississippian ocean waters did not experience a temperature decrease at the onset of the Gondwanan glaciation, but rather a marked increase in seasonal variability.

Overall, this study highlights the importance of resolving long-term changes in seasonality, using fossil carbonate shells as palaeoclimatic archives during different intervals of climate change, in both the recent and distant past, to better understand and predict long-term transformations of the climate system.

References

Angiolini et al. (2019). The giants of the phylum Brachiopoda: a matter of diet? Palaeontology, Vol. 62, Part 6, pp. 889–917

How to cite: Crippa, G., Angiolini, L., Azmy, K., Cannaò, E., Doyle, E., Della Porta, G., Murray, J., O’Connell, M., Viaretti, M., and Harper, D. A. T.: Seasonal variability at the onset of the Late Palaeozoic Ice Age: insights from Gigantoproductus shells, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12124, https://doi.org/10.5194/egusphere-egu26-12124, 2026.

Bathymetry plays a critical role in determining the occurrence and stability of landfast sea ice, although its seasonal impact on sub-Arctic ice-covered shelves has yet to be thoroughly quantified and understood. Our study explores the ways in which nearshore bathymetry and coastal topography influence the spatial distribution, seasonal persistence, and variability of landfast sea ice, with an emphasis on shallow embayments of James Bay. Our hypothesis suggests that factors like coastal orientation and bathymetry provide extent and stability to the landfast sea ice in the James Bay region, rather than being exclusively governed by marine and atmospheric factors. Using satellite-derived observations of landfast sea-ice delineations, regional bathymetric datasets, and information on coastal geomorphological configuration, this analysis will quantify statistical relationships among the landfast-ice edge extent and persistence metrics with the bathymetric thresholds and coastal orientations. Initial findings indicate that recurrent landfast ice extents are larger and their persistence is higher when there is a shallow water column, undulating bathymetry with mounds, and/or offshore features. Our observations support the hypothesis that bathymetry plays a crucial role in determining the presence and stability of landfast sea ice. By explicitly correlating bathymetry and geomorphology with landfast ice phenology and stability indicators, our research aims to advance both conceptual and quantitative understandings within coastal ice modelling frameworks and refine projections concerning the response of landfast sea ice to ongoing Arctic amplification and climate change.

How to cite: Banerjee, D., Gupta, K., and Mukhopadhyay, A.: Geomorphological controls on the persistence and extent of Landfast Sea Ice in James Bay Region, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15851, https://doi.org/10.5194/egusphere-egu26-15851, 2026.

Physical geomorphometry is young way that describe land surface morphology through gravitational energy and mass and energy movement. Unlike statistical and general geomorphometric approaches, physical geomorphometry bridging land surface characteristics and fundamental physical processes allows to interpret geomorphological primitives from genetic point of view. In this study we incorporated latest achievements of physical geomorphometry concept to demonstrate a transition from theoretical aspects to practical applications of the concept.

In the research we applied a set of physical geomorphometric (PG) indices that describes landform development from different points of view. Moreover, we used a modified algorithm of physically based elementary land-surface segmentation algorithm that integrates dynamic least-squares DEM generalization with object-based image analysis. The method is evaluated across contrasting environments, including glacial and karst landscapes, and is further extended to marine settings for seabed landform classification. Key contribution is the application of PG signature concept that unify the set of PG indices and therefore quantitatively describes landforms based on the balance and magnitude of geomorphic energies.

Our results demonstrate that the approach allows us to obtain genetically interpretable landforms both in terrestrial and submarine landscapes. Physical geomorphometric signature is highly effective in landform groups comparison and detection of each group’s potential affinity to development i.e. their disequilibrium. It also helped us to define transitional forms of landforms that are usually overlooked by general geomorphological methods.

Overall, the work highlights robustness and applicability of the concept of physical geomorphometry in various application in geosciences and beyond, that was partially demonstrated in the research.

How to cite: Popov, A. and Minár, J.: Physical geomorphometry: From a concept to practical applications, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17175, https://doi.org/10.5194/egusphere-egu26-17175, 2026.

The Tel River, a major tributary of the Mahanadi River in eastern India, exhibits strong spatial and temporal variability in flow and sediment dynamics due to its monsoon-driven hydrology, heterogeneous terrain, and increasing human interventions. Soil erosion and sediment transport, although naturally driven by rainfall and surface runoff, have been significantly altered by agriculture, urbanization, and water management structures, leading to changes in soil loss, sedimentation, and degradation of water resources. Therefore, in this study, the production of soil erosion in the Tel River Basin is estimated using the Revised Universal Soil Loss Equation (RUSLE), while riverine sediment transport is simulated using ANUGA-Sed, a two-dimensional shallow-water hydrodynamic and sediment transport model based on a finite-volume scheme. The ANUGA flow and sediment modules were calibrated and validated using observed discharge and suspended sediment data from multiple gauging stations along the Tel River. Parallel simulations performed on the Param Pravega high-performance computing systems significantly reduced computation time while maintaining numerical accuracy, enabling high-resolution modelling of the entire Tel River Basin. The model was further evaluated for elasticity, computational accuracy, and optimal grid distribution per node on the HPC system, demonstrating robust scalability and efficient utilization of computational resources.

The model results show strong agreement with observations, with errors in net erosion and deposition generally below 10%. The simulations successfully reproduce the spatial patterns of sediment generation, transport, and deposition along the river network. Importantly, the model provides new insights into sediment dynamics between gauging stations where direct measurements are unavailable and captures cross-sectional channel changes associated with sediment transport processes. These results were further validated using field-based suspended sediment data collected in October 2023 at intermediate river locations using portable sampling instruments. The simulations reveal distinct zones of high erosion and deposition that are critical for understanding flood conveyance and channel stability. Overall, the results confirm that ANUGA-Sed can reliably simulate suspended sediment transport and riverbed changes in monsoon-dominated river systems.

How to cite: Dahiwale, A. V., Dutta, U., Singh, Y. K., Yendargaye, G., Prabhu, T. S. M., and Muddu, S.: FROM CATCHMENT TO CHANNEL: HIGH-PERFORMANCE PARALLEL MODELING OF SEDIMENT TRANSPORT IN THE TEL RIVER BASIN USING ANUGA Sed, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19944, https://doi.org/10.5194/egusphere-egu26-19944, 2026.

We conducted a two-month-long cryoseismic monitoring study in the Schirmacher Oasis, East Antarctica, to investigate icequake activity caused by the movement and melting of ice sheets. For this purpose, we deployed a Raspberry Shake seismometer on the Antarctic land and ice sheet for a month. Through a comparative analysis of the recorded seismic data, we gained insights into ice dynamics and diurnal icequake patterns. The Raspberry Shake instrumentation, powered by solar energy, offers a cost-effective approach for establishing a dense seismic network. During installation, the seismometer, solar controller, and Li-ion battery were housed in a wooden box lined with nitrile foam for insulation. The analysis suggests that icequake detections follow a distinct diurnal pattern, with more events occurring during the daytime. Furthermore, we also observe interdependence between icequake detections and high wind speeds.We use a multi STA/LTA approach for event detection on a continuous 11-day period while the seismometer was on ice. We detect 2249 icequake events, which are further manually classified into three categories. More than half of icequakes (67%) belong to a shallow origin and some are indicative of deep icequakes (9%).These findings highlight the need for a denser seismic network and more detailed investigations to further understand the impact of climate change on melting ice sheets.

How to cite: Sattasi, N. S., Silwal, V., Tm, M., Ahamad, A., Suthar, A., and Negi, S. S.: Cryoseismic monitoring in the Schirmacher Oasis, East Antarctica, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19976, https://doi.org/10.5194/egusphere-egu26-19976, 2026.

River deltas play a crucial role in the transport of sediments and nutrients between river catchments and the sea. Scientific studies have demonstrated that Arctic deltas have a significant potential for sediment retention. Ongoing climate change is accelerating the thawing of permafrost, which largely constitutes the substrate of Arctic deltas, thereby affecting the morphological and hydrological evolution of these low-lying tundra systems.

The aim of this study is to estimate changes in the surface area and flood storage capacity of deltaic lakes using remote sensing methods. Optical and radar satellite data from Sentinel-2 and RADARSAT-2 were used, obtained under a grant from the Canadian Space Agency (application no. RCM CSA-RC-FORM-0003), together with advanced tools for spatial and radar data analysis. The selected study area is an eastern part of the Mackenzie River Delta (Canada, Northwest Territories), namely Big Lake, located near the city of Inuvik, approximately 130 km from the Beaufort Sea. The Big Lake is a through-flow lake with an area of about 800 ha. It is part of a system of approximately 2,000 lakes that maintain year-round connectivity with the East Channel, one of the main distributary channels conveying water within the delta.

The presented results are based on satellite and hydrological analyses conducted at the beginning of the ice-free water period, occurring at the turn of May and June. The study includes a comparison of satellite observations with gauge data. To determine the extent and volume of floodwaters, the Normalized Difference Water Index (NDWI), advanced radar data analyses, and statistical analyses of hydrological data from Water Survey of Canada (WSC) were applied. Satellite imagery acquired during open-water seasons made it possible to delineate shoreline extents and the associated water surface elevations. Selected years from the period 2011–2024 were analysed; for example, it was estimated that at the turn of May and June 2024 the lake stored approximately 8.2 million m³ of water over a period of 49 days.

Considering sediment transport, the Mackenzie River is the largest supplier to the Arctic Ocean, delivers more than 100 million tonnes of sediment annually. Previous studies characterise these sediments as predominantly fine-grained fractions that are easily transported. The presence of an organic-rich catchment combined with the magnitude of fluvial sediment transport highlights the importance of understanding the mechanisms governing sediment distribution, quantities, and areas of deposition within the delta system.

This research is being conducted with the permission of the Government of Canada – North West Territories (NWT) – research licence number 17694 which was issued under application number 6131 and financed by the Polish Ministry of Education and Science - National Research Agency, title: Evaluation of the settling velocity and trapping capacity of sediments in lakes in the Great Arctic River deltas, grant no. 2023/50/O/ST10/00597.

How to cite: Ciepłowski, D. and Habel, M.: Remote sensing analysis of water dynamics within floodplain lakes in the eastern part of the Mackenzie River delta, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20785, https://doi.org/10.5194/egusphere-egu26-20785, 2026.

The non-linear feedback mechanisms and interactions between discharge-sediment supply and instream (riparian) vegetation cover generate spatio-temporal heterogeneity in braided channel forms. The present study examines such relationships among three contrasting braided rivers of India: the Brahmaputra (highly braided), the Brahmani (weakly braided) and the Netravathi (meandering-braided). Long term JRC Surface water layer, vegetation-water remote sensing indices, numerical model derived hydrological datasets and periodic field visits have been integrated to understand the vegetation–hydrology–sediment coupling across these braided river systems.  The results show that the channel forming discharges in the Brahmaputra shows a hierarchical level and extreme events dominate over the effect of sparse vegetated landforms. In weakly braided reaches, channel-in-channel form oscillates between two extreme nodes depending upon the intensity of disturbing events. For rivers with meandering-braided transition form, channels are relatively stable and riparian vegetation cover generate a stable geometry and absence of floodplain sediment storage.   

How to cite: Pradhan, C.: Integrating Google Earth Engine Cloud Computing and Fluvial Surveys to Quantify Vegetation–Hydrology–Sediment Coupling in Contrasting Braided River Systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21498, https://doi.org/10.5194/egusphere-egu26-21498, 2026.

Cryosphere-fed rivers drain glacier, snow, and permafrost landscapes and are characterized by glacial, nival, pluvial and mixed hydrological regimes. Such river systems originate from high-mountain areas and polar regions, and transport water, sediment, nutrients, and organic carbon downstream, underpinning the freshwater and coastal ecosystems and supporting the lives of more than one-third of the world's population. In response to the amplified climate change, accelerating glacier-snow melt and permafrost thaw, the cryosphere-fed rivers are overall becoming warmer, wider and muddier associated with markedly increasing river turbidity and suspended sediment concentrations. In this talk, I will present the observed and modelled changes in cryosphere-fed rivers and examine their implications for channel mobility and the carbon cycle across both High Mountain Asia and the pan-Arctic. To better assess the impacts of changing climate on the functions and services of river ecosystems in strategically important cold regions, I highlight the pressing need to integrate multiple-sourced river observations, to develop empirical, physics-based, and AI-based river flux models, and to promote interdisciplinary scientific collaboration. The innovative system approach would best come from the creation of an interdisciplinary collaborative initiative, where geomorphologists, climatologists, ecologists, glaciologists, permafrost scientists, hydrologists, and civil engineers work together to establish an integrated cryosphere-water-sediment-carbon-ecology observation platform that facilitates the mechanism understanding and development of novel and powerful models. Furthermore, dialogues and collaboration between international scientists, stakeholders, local communities, and policymakers would help to bridge the gaps between state-of-the-art scientific findings and practicable adaptation strategies.

How to cite: Li, D.: Cryosphere-fed rivers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2198, https://doi.org/10.5194/egusphere-egu26-2198, 2026.

Desert pavements are widespread geomorphic features in drylands, but their distribution and characteristics have not been adequately characterized. They play a critical role in the atmospheric dust cycle where they control dust emission and entrainment. Against this backdrop, the goal of this project is to map the distribution and physical characteristics of desert pavements and related stone-armored surfaces using field evidences, terrain analysis and remote sensing data, and machine-learning models. Our focus is on Namibia, where we start from an initial distribution assessment generated by GIS-based multicriteria suitability analysis.

Ground-truth data acquisition is conducted as an extensive field survey to document desert pavements across regional environmental gradients. Following zigzag transects, we record pavement characteristics including surface roughness, clast size and weathering features, and geomorphic information including micro-topography and signs of water erosion. Special emphasis is placed on the detection and characterization of vesicular horizons discriminating desert pavements against other stone-armored surfaces. We use UAV photogrammetry as well as ground-level optical and thermal surface imaging for detailed documentation and to facilitate precise local-scale analyses. These ground-truth observations will provide a representative empirical basis for analyzing pavement-forming processes and will support the development of a hybrid geospatial artificial intelligence (GeoAI) framework that integrates optical and thermal remote sensing data with terrain attributes derived from digital elevation models for digital soil mapping at a high spatial resolution.

As a preparatory step guiding the field surveys, we refine our recently proposed Desert Pavement Potential Index (DPPI) by incorporating additional environmental constraints. The updated index (DPPI v2) integrates a diurnal soil temperature range layer and a desert bloom index (DBI) into the existing index that is based on general precipitation, vegetation, soil texture, and disturbance patterns. The DBI, derived from a 26-year MODIS NDVI archive, allows stable pavements to be distinguished from surfaces that experience episodic greening and thus root development. A preliminary validation, limited to areas where the original DPPI suggested geomorphically plausible pavement conditions (DPPI ≥ 0.75) so as to avoid trivial contrasts with clearly unsuitable or vegetated surfaces and thereby enable a more meaningful assessment, indicates a considerable improvement in discrimination skill (area under the ROC curve: 0.864 for DPPI v2 vs. 0.779 with the original index). Visual comparison further shows that DPPI v2 produces a spatially more constrained and geomorphically coherent envelope of pavement-favorable conditions.

Taken together, the combination of field observations with multi-source GeoAI models is expected to provide a scalable framework for mapping desert pavements in Namibia, which will improve the representation of surface processes in atmospheric dust modeling.

How to cite: Bourriz, M. and Brenning, A.: Toward High-Resolution Mapping of Desert Pavements: Field Surveys and First Results from Namibia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2032, https://doi.org/10.5194/egusphere-egu26-2032, 2026.

The Hantan River basin (central–northern Korean Peninsula) is characterized by a Quaternary volcanic–fluvial landscape in which basaltic lava flows repeatedly overlie unconsolidated fluvial deposits. Beneath these lava flows, the Baeguiri Formation consists of channelized fluvial conglomerates and sands with associated overbank silts and clays, unconformably overlying Devonian basement units. While the emplacement ages of overlying basalts are relatively well constrained by K–Ar and ⁴⁰Ar/³⁹Ar dating, the depositional and burial timing of the underlying fluvial conglomerates remains poorly constrained and controversial. Previous age estimates for the Baeguiri Formation, derived indirectly from basalt contact ages, fission-track, and TL/OSL methods, provide only partial constraints and may be affected by inheritance, post-depositional reworking, and uncertainty in the time lag between sediment deposition and lava burial.

To directly date the burial of the fluvial conglomerates and to assess potential temporal heterogeneity among key outcrops, we apply cosmogenic radionuclide (CRN) burial dating using paired ¹⁰Be and ²⁶Al measurements on quartz-bearing gravel from conglomeratic units of the Baeguiri Formation at four representative sites in the Hantan River system: Eundaeri (Chatan Stream tributary), Baeguigyo Bridge, Jangjingyo Bridge, and Hantangang Dam along the mainstem Hantan River. At all sites, the conglomerates are fully covered by multi-meter-thick basalt flows, locally associated with pillow lavas and slabby flow-top structures, indicating rapid burial and long-term attenuation of cosmic-ray exposure. Burial ages are calculated using isochron approaches to account for variable pre-burial exposure histories and possible partial reworking within fluvial deposits.

The resulting burial ages provide direct chronological constraints on the timing of isolation of the Baeguiri Formation from surface processes, allowing us to (1) Test whether burial of the fluvial conglomerates by basalt flows was synchronous across different outcrops, (2) Quantify spatial and temporal heterogeneity in sedimentation–burial events within the Baeguiri Formation, and (3) Evaluate implications for refining stratigraphic relationships between fluvial deposits and multi-stage basalt emplacement in the Hantan River volcanic–fluvial succession. This study highlights the effectiveness of CRN burial dating for directly constraining the age of basalt-buried fluvial conglomerates in complex Quaternary volcanic plateaus.

How to cite: Choi, Y., Lee, H., Lee, T.-H., and Han, M.: Cosmogenic 10Be–26Al Isochron Burial Dating of Basalt-Capped Fluvial Deposits in the Hantan River Basin, Korea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2298, https://doi.org/10.5194/egusphere-egu26-2298, 2026.

Complex landslides contain internally heterogeneous zones that may respond differently to reactivation, complicating tree-ring based chronologies of slope activity. This study combines dendrogeomorphological analysis with electrical resistivity tomography (ERT) to test whether geophysics-based zonation could explain the spatial variability of tree-ring disturbances within a large complex landslide. ERT profiles and geomorphological mapping delineated three mechanically distinct zones: a downslope shallow-landslide sector (S zone), a moisture-rich gap infilled by weakly consolidated material (G zone), and an adjacent compact block with tension cracks (B zone). In total, 200 Norway spruce (Picea abies (L.) H. Karst) were analysed for reaction wood (RW) and abrupt growth suppression (GS). RW intensity was quantified for each affected ring and GS classified by relative ring-width reduction.

RW clearly dominates across the landslide. The S zone shows the highest stem inclinations and RW intensities, indicating enhanced shallow deformation, whereas RW duration is similar among zones. GS occurs everywhere but is proportionally most frequent in the B zone. Correlation analyses show that in the S and G zones, RW intensity and duration relate significantly to stem inclination, while no significant relationships appear in the B zone.

These results demonstrate that internal landslide heterogeneity, as delineate by ERT, is reflected in tree-ring responses. Geophysics-based zonation offers an effective framework for interpreting growth disturbances and improves dendrogeomorphic reconstructions of complex slope movements.

How to cite: Schlesinger, F. and Šilhán, K.: Geophysics-based landslide zonation explains spatial variability in tree-ring growth disturbances, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5207, https://doi.org/10.5194/egusphere-egu26-5207, 2026.

Hard coal spoil heaps form distinctive anthropogenic landforms and highly dynamic geosystems within post-mining landscapes. Their extreme physical-geographical conditions arise from interactions between heterogeneous substrate properties, distinct geomorphic processes, specific hydrological regimes, microclimatic anomalies, and thermal activity. Although thermal activity and contamination have been widely studied due to their environmental relevance, research on spoil heaps remains fragmented and often focused on isolated components of the system. Integrated, holistic approaches that explicitly link individual subsystems are still largely lacking. This contribution presents a synthesis of current global knowledge and introduces a conceptual geosystem model demonstrating that morphometric variables (local relief, slope, and aspect) act as primary drivers of spoil heap dynamics. The model captures cascading interactions among geomorphological, hydrological, thermal, and microclimatic processes and provides a unifying framework for interpreting spoil heaps as complex anthropogenic geosystems. This approach provides a basis for future interdisciplinary research and supports a more systematic understanding of spoil heap evolution, their environmental impacts, and potential future landscape functions.

How to cite: Bedrunková, N. and Lenart, J.: Hard Coal Spoil Heaps as Complex Geosystems: A Conceptual Framework Based on Physical-Geographical Controls, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5217, https://doi.org/10.5194/egusphere-egu26-5217, 2026.

The Republic of Moldova is known for the high frequency of landslides on small slopes and within agricultural areas. As a part of the transboundary research project “The impact of European agricultural policies on land use: Romania's experience and lessons for the Republic of Moldova in a European perspective – MapLURoMd”, this study aims to evaluate the spatial distribution of landslides in Anenii Noi District, Republic of Moldova, using GIS-based analysis and field verification. The research is based on 2020 orthophotographic images, processed in ArcGIS 10.4.1 and validated by GPS-based ground surveys. Landslide occurrence was analysed in relation to three morphometric parameters: slope gradient, altitude, and slope exposure. The applied methodology enabled the identification and mapping of landslide-affected areas and the assessment of their relationship with terrain characteristics. The lithological composition, a known factor for landslide development in general, was not important in our case due to a lack of regional diversity. As a result, several thematic maps were generated, including landslide distribution, altitude, slope, and slope exposure maps. The proportion of areas affected by landslides within different morphometric classes was also quantified. The results highlight zones of increased landslide susceptibility, providing valuable support for landslide risk mitigation, territorial planning, and land management within the Republic of Moldova's agricultural development policy.

How to cite: Cantir, A., Chiriac, I., Crivova, O., Curcubat, S., Sirodoev, G., Cracu, G.-M., Nicoara, R.-G., Paraschiv, M., Schvab, A., Secareanu, G., Vaidianu, N., and Sirodoev, I.: GIS-based landslide susceptibility assessment on low slopes: the case study of Anenii Noi district, the Republic of Moldova, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7278, https://doi.org/10.5194/egusphere-egu26-7278, 2026.

Many scholars believe that the core part of the Taiwan orogen, with rapid tectonic uplift for millions of years but only 3000 - 4000 m high, has obtained a topographic steady state, in which the tectonic uplift is balanced by erosion. Steady-state topography is expected to be dominated by steep slopes reaching the angle of repose. With this new notion, the existence of gentle slopes/rivers in the core part of the orogen, which has been noted by Japanese scholars a century ago, was recently overlooked, and those gentle landforms were regarded as “transient” features. We thoroughly examined the topography of the orogen and confirmed the observations by the Japanese scholars: (1) the gentle slopes/rivers, surrounded by steep slopes/knickzones downward, are mainly exhibited on or near drainage divides; (2) the gentle rivers show a great range of width and sinuosity; those flowing in wide valleys are commonly associated with ponds or wetlands; (3) the slopes drained by the gentle rivers can be gentle or steep; the gentle slopes are typically underlain by thick, heavily weathered colluviums; (4) many major drainage divides follow rounded ridges with gentle slopes on both sides; (5) the gentle slopes/rivers are widely exhibited throughout the orogen, from north to south, from west to east, and from low to high elevations.

The juxtaposition between the observed gentle slopes/rivers and the steep slopes/knickzones around them has suggested the change of river behavior from incision-limited to incision-dominated, associated with an increase in landslide activity. The spatial configuration of these landforms further shows re-organization of drainage systems, including river capture and its resulting contraction/expansion of catchments, adjusting to the inferred geomorphic change. Through these analyses, we have confidence that the observed gentle slopes/rivers are better treated as relict landforms preserved on/near ridge tops, not “transient” features developed after the loss of catchment areas as suggested by some scholars.            

Our inferred geomorphic change fits well with the known thermochronological data and the data from the sediment-hydrogen-isotope-based paleo-topographic studies, which jointly show an acceleration of both crustal denudation and surface uplift starting later than 2 Ma. We propose that the orogen had long been dominated by hills when both tectonic uplift and denudation were slow (< 2 mm/yr). The uplift then accelerated (up to 6 - 8 mm/yr), triggering river incision/landsliding which progressively eroded the gentle slopes/rivers created earlier. Since then, the combined river/hillslope erosion has not been able to balance the tectonic uplift, which allowed the preexisting gentle landforms to be raised to high elevations (as long as they are preserved). Once these gentle landforms were raised to elevations > 3000 m, they facilitated snow accumulation and thus, glaciation, during the last glacial period (i.e. the relict cirques and U-shape valleys currently preserved in the orogen were strongly inherited from the preexisting gentle landforms).

How to cite: Li, F.-Y., Hsieh, M.-L., and Chang, Y.-F.: Overlooked high-elevation gentle slopes/rivers in the rapidly uplifting Taiwan orogen, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8500, https://doi.org/10.5194/egusphere-egu26-8500, 2026.

The origin of the mountains of Norway (the Scandes) is controversial. Here we show that the high-level landscape of the Southern Scandes consists mostly of three extensive, low-relief surfaces separated by escarpments. The surfaces extend across 90,000 km² and cut across rocks of different lithologies and post-date the Jurassic surface on the slopes of the Southern Scandes. The surfaces are peneplains graded by river erosion to a base level of sea level during the Late Cretaceous, Paleocene and Miocene. They were all subsequently slightly folded, tilted and uplifted to their present elevations of 1000–1400, 1300–1700 and 1600–1900 m, forming a landscape with distinct steps. The final uplift began in the early Pliocene and caused incision of fluvial valleys and exhumation of the Jurassic surface stripped from its protective cover of Jurassic and younger sediments. Many fluvial valleys were reshaped into glacial valleys and fjords during the Quaternary, while the stepped peneplains kept much of their pre-glacial appearance. The Scandes have not remained high since the Caledonian Orogeny, they are not shaped by footwall uplift and the plateau surfaces are not the result of glacial erosion. The repeated episodes of subsidence and uplift, burial and exhumation that shaped the high-level landscape of the Southern Scandes were driven by sub-lithospheric forces and intra-plate stress. This landscape resembles the elevated passive continental margins (EPCMs) that occur globally in all climate zones. The observations reported here provide important constraints on studies of the tectonic development of western Scandinavia and other EPCMs.

How to cite: Bonow, J., Chalmers, J., and Japsen, P.: The High Plains of Southern Norway: Result of Late Mesozoic – Cenozoic Episodic Tectonics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10763, https://doi.org/10.5194/egusphere-egu26-10763, 2026.

The Central Apennine is a key sector for karst studies in Italy, nevertheless recent systematic mapping of epigean karst landforms remains scarce. Despite extensive research on hypogene karst and springs, there is a lack of region-wide, high-resolution mapping of surface karst features using modern GIS-based approaches. This study addresses that gap by producing a new comprehensive, multiscale investigation, classification and mapping of karst landforms and landscapes in Central Italy (Abruzzo region)

Carbonate terrains, mainly Jurassic–Cretaceous limestones, cover about 70% of the chain sector of the region and are organized into morpho-structural units bounded by active normal faults. These tectonic features have fragmented ancient karst surfaces and influenced the development of endoreic basins and fluvio-karst drainage patterns. To address this complexity, the research workflow combined traditional geomorphological interpretation with semi-automatic detection techniques applied to multiresolution DTMs (10 m and 5 m), supported by 1 m LiDAR data where available.

The methodology was structured across three scale ranges: (i) small scale (1:200,000–1:50,000) for the definition of carbonate karst morpho-units (CKMUs); (ii) intermediate scale (1:50,000–1:25,000) for the delineation of the main karst areas within CKMUs; and (iii) large scale (1:25,000–1:5,000) for detailed mapping and classification of individual landforms. At the lower scale ranges manual remote mapping was used for larger features, whereas at higher scale, semi-automatic procedures were employed to map smaller features. The applied methods included: (i) fill-sinks algorithms for closed depressions (e.g. dolines, uvala); (ii) raster stacking of DTM-derived parameters (Sky View Factor, Topographic Position Index, curvature) for open depressions; and (iii) supervised filtering of karst valleys from the regional drainage network at 1:5,000 scale.

All outputs were validated through remote checks and field surveys in four representative test areas.

The research workflow led to the definition of:

• 12 CKMUs at regional scale, according to tectonic, morphostructural, and hydrogeological boundaries, which also provided criteria for defining additional sub-units;
• 347 main karst areas at intermediate scale, classified into six types based on landforms clustering: (1) areas with solution dolines; (2) areas with collapse dolines; (3) areas with karst valleys; (4) tectono-karst plains; (5) areas with solution dolines and karst valleys; (6) areas with solution dolines and tectono-karst plains;
• 53,887 landforms mapped at large scale, grouped into five classes: (1) 4,371 closed depressions (closed-contour dolines); (2) 30,247 open depressions (open-contour dolines); (3) 130 karst plains (large uvala, small poljes); (4) 14 poljes; and (5) 19,125 karst valleys (dry or blind valleys). Classification thresholds of depressions were based on surface extension (0.04 km² between dolines and karst plains; 2 km² between karst plains and poljes), with few outliers due to manual adjustments. The resulting dataset was compiled into a regional map (represented at 1:100,000 scale) and stored in a geospatial archive.

This integrated approach demonstrates the effectiveness of combining classic and GIS-based techniques for regional-scale karst feature mapping. The new map and archive provide a replicable framework for further studies and an essential tool for hydrogeological modelling, hazard assessment, and geodiversity management.

How to cite: Morelli, F. and Piacentini, T.: Regional mapping of carbonate karst landforms and landscape in Central Apennines (Abruzzo, Central Italy), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17764, https://doi.org/10.5194/egusphere-egu26-17764, 2026.

Aotearoa New Zealand’s dynamic geological landscape, shaped by complex tectonic activity, rapid uplift, and diverse climatic conditions, provides an exceptionally valuable environment for the application of trapped-charge methods across multiple Earth science disciplines. While significant trapped-charge research has already been conducted in New Zealand, substantial opportunities remain to expand this work. Techniques such as optically and infrared stimulated luminescence (OSL and IRSL) and electron spin resonance (ESR), employed for sediment and bedrock dating, rock-surface exposure dating, burial dating, palaeothermometry, or low-temperature thermochronometry, offer powerful tools for investigating geological and geomorphological processes across timescales ranging from decades to millions of years.

In surficial deposits, luminescence and ESR dating can constrain soil development and sediment stratigraphy, as well as the timing of processes such as sand dune migration, fluvial terrace formation, landslides, glacial retreat, archaeological site occupation, and coastal progradation. Single-grain and multi-signal approaches enable reconstruction of sediment transport pathways, provenance analysis, and deposition rates, providing insight into river dynamics, earthquake-triggered liquefaction, and the recurrence of mass-wasting events. When applied to bedrock and fault zones, trapped-charge thermochronometry and rock-surface dating can record low-temperature cooling histories, uplift rates, exhumation patterns, and fault activity, bridging the temporal gap between short-term surface processes and long-term crustal evolution, and offering complementary insights into the interplay between tectonics, climate, and landscape evolution.

Trapped-charge methods can also support geothermal studies and paleoclimate reconstructions, linking surface processes to tectonic and climatic forcing across New Zealand’s diverse environments. By integrating these trapped-charge techniques with geological, geomorphic, and geodetic observations, we can gain a deeper understanding of landscape evolution, active tectonics, seismic hazards, and resource management in the geologically active region of Aotearoa New Zealand.

How to cite: Bouscary, C., Nicol, A., and Shulmeister, J.: Luminescence dating and thermochronometry for Earth science applications in Aotearoa New Zealand: opportunities and potential, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19314, https://doi.org/10.5194/egusphere-egu26-19314, 2026.

Proglacial meltwater systems played a key role in shaping post-glacial landscapes in parts of Lithuania, forming a variety of landforms such as meltwater channels, outwash plains, glaciofluvial valleys, terrace systems and related sedimentary landforms. Although these landforms have been widely described in terms of glacial and proglacial processes, their role in structuring present-day environmental conditions has received comparatively less attention.

In this study, we examine selected proglacial meltwater geomorphic units in Lithuania and explore their environmental properties, with particular emphasis on sedimentological characteristics, soils, vegetation patterns, and land-use structure. Geomorphic units were identified through interpretation of LiDAR-derived digital elevation models supported by geological mapping. These data were combined with spatial information on soils, land cover, and landscape structure to characterise the environmental context of individual units.

The results explore whether and how proglacial meltwater geomorphic units are associated with variations in environmental characteristics within Lithuania’s post-glacial landscapes.

The study considers the relevance of proglacial meltwater geomorphic units as a framework for interpreting landscape organisation and environmental properties. This perspective may contribute to improved landscape interpretation, environmental assessment, and spatial planning in formerly glaciated regions.

How to cite: Kazlauskas, M. and Mačiulaitis, J.: Environmental Properties of Proglacial Meltwater Geomorphic Units in Lithuania’s Post-Glacial Landscapes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19801, https://doi.org/10.5194/egusphere-egu26-19801, 2026.

Historical maps are a very valuable source of information on the morphology of rivers in an earlier, more natural state. However, these maps provide no or limited information on river depth, whereas knowledge of river depth distribution is required for the calculation of historical bedload. In times when rivers are impacted by multiple pressures on the sediment cycle, such knowledge would help to define a range of realistic bedload supplies required for successful river restoration.

This paper presents a tool that can be used to estimate the elevation distribution of the river bed and the resulting bedload based on active and bankfull channel widths obtained from maps. A power function represents the width-depth curve and is fitted to the mean active and bankfull widths and the respective discharge capacities. The applicability to historical maps of the Upper Drava River was confirmed by archive material on historical lowest flow depths.

How to cite: Klösch, M., Hohensinner, S., Dunst, R., Rindler, R., and Habersack, H.: Estimation of river depths and bedload based on dimensions in plan view, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20389, https://doi.org/10.5194/egusphere-egu26-20389, 2026.

Tunnel valley formation and orientation are primarily controlled by the hydraulic gradient beneath large ice sheets. However, recent onshore studies from Denmark have motivated the hypothesis that deep fault systems may also influence the position and orientation of shallow erosional features like tunnel valleys. Onshore, this hypothesis has been supported by observed similarities in the overall orientation and spatial trends of deep fault systems and shallow erosional features. These correlations have been attributed to reactivation of the faults due to loading and unloading by large ice sheets as well as subtle variations in sediment strength caused by the deep structural features.

Importantly, these onshore studies are based on interpretations of transient electromagnetic data and sparse 2D reflection seismic data. Offshore where reflection seismic data is almost exclusively applied, the onshore methods cannot be applied directly, leaving the question of deep–shallow correlations largely unexplored.

In order to test this hypothesis further, we have gathered previously mapped tunnel valleys and deep geological structures offshore, combined with new interpretations from various reflection seismic data sets and analyzed the orientation and position of the tunnel valleys on both regional and local scale using a geostatistical approach specifically developed for this study. This approach allows us to distinguish between local and regional-scale correlations, which can support the hypothesis offshore while also be applied onshore. The large-scale analysis can also highlight other trends within the extensive suite of buried tunnel valleys in the North Sea, including the influence of salt structures, multiple tunnel valley generations and past ice sheet dynamics.

How to cite: Prins, L. T., Allart, L., Madsen, R. B., Aabø, T. M., Boldreel, L. O., Andresen, K. J., Clausen, O. R., Singhroha, S., and Sandersen, P.: Do deep geological structures influence shallow Quaternary erosional patterns in the North Sea?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21128, https://doi.org/10.5194/egusphere-egu26-21128, 2026.

Since the robust performance of Long Short-Term Memory (LSTM) networks was established, their physics-awareness and interpretability have become central topics in hydrology. Seminal works (e.g., Lees et al. (2022)) have argued that LSTM internal states spontaneously capture hydrological concepts, and suggested that cell states can represent soil moisture dynamics despite not being explicitly trained on such data. Conversely, more recent studies (e.g., Fuente et al. (2024)) demonstrated that mathematical equifinality causes non-unique LSTM representations with different initialisations.

In this work, we report an arguably more systematic "bug" in the software environment that causes instability in internal states. We initially aimed to investigate how internal states behave differently when trained with or without historical observation data. We encountered this issue while reassembling a computational stack and attempting to replicate the initial results, as the original Docker environment was not preserved. While random seeds have been indicated to lead to different internal state trajectories, we found the computational backend (e.g., changing CUDA versions, PyTorch releases, or dependent libraries) also produces them. These are the findings:

• In gauged catchments: Discharge predictions remained stable (in one catchment, NSE was 0.88 ± 0.01) across computational environments, yet the internal temporal variations (e.g., silhouette, mean, and std of cell states) fluctuated noticeably.
• In pseudo-ungauged scenarios: The prediction performance itself became more reliant on the computational environment (in the same catchment, NSE dropped to 0.31 ± 0.15), yet the internal temporal variations of the cell states fluctuated only as much as they did during the gauged scenario.

These findings suggests that instability in the computational environment poses not only a risk of altering interpretability in training (by altering internal states) but also casts doubt on reliability in extrapolation (by altering outputs).

It is worth mentioning that we confirmed this is not a replicability issue; completely identical cell states and predictions are produced when the computational environment, seeds, and training data are held constant. We argue that such stability must be established as a standard benchmark before assigning physical meaning to deep learning internals.

How to cite: Nagumo, R., Woods, R., and Rico-Ramirez, M.: The Unreliable Narrator: LSTM Internal States Fluctuate with Software Environments Despite Robust Predictions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1897, https://doi.org/10.5194/egusphere-egu26-1897, 2026.

Moments or periods of struggle not only propel scientists forward, but sharing these experiences can also provide valuable lessons for others. Indeed, the current bias towards only publishing ‘positive’ results arguably impedes scientific progress as mistakes that are not learnt from are simply repeated. Here we present a new article type in EGU journals covering LESSONS learnt to help overcome this publishing bias. LESSONS articles describe the Limitations, Errors, Surprises, Shortcomings, and Opportunities for New Science emerging from the scientific process, including non-confirmatory and null results. Unforeseen complications in investigations, plausible methods that failed, and technical issues are also in scope. LESSONS thus fit the content of the BUGS session and can provide an outlet for articles based on session contributions. Importantly, a LESSONS Report will offer a substantial, valuable insight. LESSONS Reports are typically short (1,000-2,000 words) to help lower the barrier to journal publication, whilst LESSONS Posts (not peer-reviewed, but with a DOI on EGUsphere) can be as short as 500 words to allow early-stage reporting. LESSONS aim to destigmatise limitations, errors, surprises and shortcomings and to add these to the published literature as opportunities for new science – we invite you to share your LESSONS learnt.

Finally, a big thank you from this paper’s ‘core’ writing team to the wider group who have helped shape the LESSONS idea since EGU GA in 2025, including PubCom and in particular its Chair Barbara Ervens.

How to cite: Hillier, J., Proske, U., Gaillard, S., Blume, T., and Queiroz Alves, E.: New EGU Manuscript Types: Limitations, Errors, Surprises, and Shortcomings as Opportunities for New Science (LESSONS), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2771, https://doi.org/10.5194/egusphere-egu26-2771, 2026.

Photocatalysis is frequently presented in the literature as a straightforward route toward efficient degradation of pollutants, provided that the “right” material is selected. Layered double hydroxides (LDH) are often highlighted as promising photocatalysts due to their tunable composition and reported activity in dye degradation. Motivated by these claims, this study evaluated LDH as mineral analogs for photocatalytic water treatment, ultimately uncovering a series of unexpected limitations, methodological pitfalls, and productive surprises.

In the first stage, Zn/Cr, Co/Cr, Cu/Cr, and Ni/Cr LDHs were synthesized and tested for photocatalytic degradation of methylene blue (0.02 mM) and Acid Blue Dye 129 (0.3 mM). Contrary to expectations,¹ photocatalytic performance was consistently low. After one hour of irradiation, concentration losses attributable to photocatalysis did not exceed 15%, while most dye removal resulted from adsorption. Despite extensive efforts to optimize synthesis protocols, catalyst composition, and experimental conditions, this discrepancy with previously published studies could not be resolved.

To overcome limitations related to particle dispersion, surface accessibility, and charge-carrier separation, a second strategy was pursued by incorporating clay minerals as supports.² Zn/Cr LDH, identified as the most active composition in preliminary tests, was coprecipitated with kaolinite, halloysite, and montmorillonite. Experiments with methylene blue (0.1 mM) and Acid Blue 129 (0.3 mM) demonstrated enhanced adsorption capacities. However, photocatalytic degradation efficiencies remained poor, typically below 10% after one hour, indicating that apparent performance gains were largely adsorption-driven rather than photochemical.

This failure proved to be a turning point. Instead of abandoning LDH entirely, they were combined with graphitic carbon nitride (GCN) to form a heterostructure.³ This approach resulted in a dramatic improvement: after optimization of the synthesis protocol, 99.5% of 1 ppm estrone was degraded within one hour.⁴ Further modifications were explored by introducing Cu, Fe, and Ag into the LDH/GCN system. While Cu and Fe suppressed photocatalytic activity, silver, at an optimized loading, reduced estrone concentrations below the detection limit within 40 minutes.⁵

This contribution presents a full experimental arc - from promising hypotheses that failed, through misleading adsorption-driven “successes,” to an ultimately effective but non-intuitive solution - highlighting the value of negative results and surprises as drivers of scientific progress.

This research was funded by the AGH University of Krakow, grant number 16.16.140.315.

Literature:

1            N. Baliarsingh, K. M. Parida and G. C. Pradhan, Ind. Eng. Chem. Res., 2014, 53, 3834–3841.

2            A. Í. S. Morais, W. V. Oliveira, V. V. De Oliveira, L. M. C. Honorio, F. P. Araujo, R. D. S. Bezerra, P. B. A. Fechine, B. C. Viana, M. B. Furtini,
              E. C. Silva-Filho and J. A. Osajima, Journal of Environmental Chemical Engineering, 2019, 7, 103431.

3            B. Song, Z. Zeng, G. Zeng, J. Gong, R. Xiao, S. Ye, M. Chen, C. Lai, P. Xu and X. Tang, Advances in Colloid and Interface Science, 2019, 272, 101999.

4            A. Jędras, J. Matusik, E. Dhanaraman, Y.-P. Fu and G. Cempura, Langmuir, 2024, 40, 18163–18175.

5            A. Jędras, J. Matusik, J. Kuncewicz and K. Sobańska, Catal. Sci. Technol., 2025, 15, 6792–6804.

How to cite: Jędras, A. and Matusik, J.: False Starts and Silver Linings: A Photocatalytic Journey with Layered Double Hydroxides, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3077, https://doi.org/10.5194/egusphere-egu26-3077, 2026.

BUGS can arise in individual research projects, but also at the level of communities of researchers, leading to shifts in the scientific consensus.  These community-level BUGS typically arise from observations that are surprising to (or previously overlooked by) substantial fractions of the research community.  In this presentation, we summarize several community-level BUGS in our field: specifically, key surprises that have transformed the hydrological community's understanding of hillslope and catchment processes in recent decades.  

Here are some examples.  (1) Students used to learn (and some still do today) that storm runoff is dominated by overland flow.  But stable isotope tracers have convincingly shown instead that even during storm peaks, streamflow is composed mostly of water that has been stored in the landscape for weeks, months, or years.  (2) Maps, and most hydrological theories, have typically depicted streams as fixed features of the landscape.  But field mapping studies have shown that stream networks are surprisingly dynamic, with up to 80% of stream channels going dry sometime during the year.  (3) Textbooks have traditionally represented catchment storage as a well-mixed box.  But tracer time series show fractal scaling that cannot be generated by well-mixed boxes, forcing a re-think of our conceptualization of subsurface storage and mixing.  (4) Waters stored in aquifers, and the waters that drain from them, have traditionally been assumed to share the same age.  But tracers show that waters draining from aquifers are often much younger than the groundwaters that are left behind, and this was subsequently shown to be an inevitable result of aquifer heterogeneity. 

Several examples like these, and their implications, will be briefly discussed, with an eye to the question: how can we maximize the chances for future instructive surprises?

How to cite: Kirchner, J., Benettin, P., and van Meerveld, I.: Instructive surprises in the hydrological functioning of landscapes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4074, https://doi.org/10.5194/egusphere-egu26-4074, 2026.

Coming from geosciences, we hopefully know what we want to do. Coming from numerics, however, we often know quite well what we are able to do and look for a way to sell it to the community. A few years ago, deep-learning techniques brought new life into the glaciology community. These approaches  allowed for simulations of glacier dynamics at an unprecedented computational performance and motivated several researchers to tackle the numerous open questions about past and present glacier dynamics, particularly in alpine regions. From another point of view, however, it was also tempting to demonstrate that the human brain is still more powerful than artificial intelligence by developing a new classical numerical scheme that can compete with deep-learning techniques concerning its efficiency.

Starting point was, of course, the simplest approximation to the full 3-D Stokes equations, the so-called shallow ice approximation (SIA). Progress was fast and the numerical performance was even better than expected. The new numerical scheme enabled simulations with spatial resolutions of 25 m on a desktop PC, while previous schemes did not reach simulations below a few hundred meters.

However, the enthusiasm pushed the known limitations of the SIA a bit out of sight. Physically, the approximation is quite bad on rugged terrain, particularly in narrow valleys. So the previous computational limitations have been replaced by physical limitations since high resolutions are particularly useful for rugged topographies. In other words, a shabby house has a really good roof now.

What are the options in such a situation?

• Accept that there is no free lunch and avoid contact to the glacialogy community in the future.
• Continue the endless discussion about the reviewers' opinion that a spatial resolution of 1 km is better than 25 m.
• Find a real-world data set that matches the results of the model and helps to talk the problems away.
• Keep the roof and build a new house beneath. Practically, this would be developing a new approximation to the full 3-D Stokes equations that is compatible to the numerical scheme and reaches an accuracy similar to those of the existing approximations.
• Take the roof and put it on one of the existing solid houses. Practically, this would be an extension of the numerical scheme towards more complicated systems of differential equations. Unfortunately, efficient numerical schemes are typically very specific. So the roof will not fit easily and it might leak.

The story is open-ended, but there will be at least a preliminary answer in the presentation.

How to cite: Hergarten, S.: How useful is a new roof on a shabby house? An example from glacier modeling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4196, https://doi.org/10.5194/egusphere-egu26-4196, 2026.

“Show your working!” – is the universal phrase drilled into science and maths students to show a clear demonstration of the steps and thought processes used to reach a solution (and to be awarded full marks on the exam). 

Beyond the classroom, “show your working” becomes the methods section on every scientific paper, and is critical for the transparency and replicability of the study. However, what happens if parts of the method are considered assumed knowledge, or cut in the interests of a word count? 

An inability to fully replicate the results of a study became the unexpected glitch at the start of my PhD. Eager to familiarise myself with global climate model datasets, I set out to replicate the results of a widely cited paper which calculates the equilibrium climate sensitivity (ECS) across 27 climate models. The ECS is the theoretical global mean temperature response to a doubling of atmospheric CO₂ relative to preindustrial levels. A commonly used method to calculate the ECS is to apply an ordinary least squares regression to global annual mean temperature and radiative flux anomalies. 

Despite the simplicity of a linear regression between two variables, we obtained ECS estimates for some climate models that differed from those reported in the original study, even though we followed the described methodology. However, the methodology provided only limited detail on how the raw climate model output – available at regional and monthly scales – was processed to obtain global annual mean anomalies. Differences in these intermediate processing steps can, in turn, lead to differences in ECS estimates.

Limited reporting of data-processing steps is common in the ECS literature. Whether these steps are considered assumed knowledge or deemed too simple to warrant explicit description, we demonstrate that, for some models, they can materially affect the resulting ECS estimate. While the primary aim of our study is to recommend a standardised data-processing pathway for ECS calculations, a secondary aim is to highlight the lack of transparency in key methodological details across the literature. A central takeaway is the importance of clearly documenting all processing steps – effectively, to “show your working” – and to emphasise the critical role of a detailed methods section.

How to cite: Zehrung, A., King, A., Nicholls, Z., Zelinka, M., and Meinshausen, M.: The importance of describing simple methods in climate sensitivity literature, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4587, https://doi.org/10.5194/egusphere-egu26-4587, 2026.

Observation of atmospheric constituents and processes is not easy. As atmospheric chemists, we use sensitive equipment, for example mass spectrometers, that we often set up in a (remote) location or on a moving platform for a few-weeks campaign to make in-situ observations. All this with the goal of explaining more and more atmospheric processes, and to verify and improve atmospheric models. However, glitches can happen anywhere in an experiment, be it in the experimental design, setup, or instrumental performance. Thus, complete data coverage during such a campaign is not always a given, resulting in gaps in (published) datasets. And the issue with air is that you can never go back and measure the exact same air again. Here, I would like to share some stories behind such gaps, and what we learned from them. This presentation aims to encourage early career researchers who might be struggling with feelings of failure when bugs, blunders and glitches happen in their experiments - you are not alone! I will share what we learned from these setbacks and how each of them improved our experimental approaches.

How to cite: Pfannerstill, E. Y.: Why are there gaps in your measurements? Sharing the stories behind the missing datapoints, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5494, https://doi.org/10.5194/egusphere-egu26-5494, 2026.

Over a 24-year research period, three successive experimental investigations led to three publications, each of which falsified the author’s preceding hypothesis and proposed a revised conceptual framework. Despite an initial confidence in having identified definitive solutions, subsequent experimental evidence consistently demonstrated the limitations and inaccuracies of earlier interpretations. This iterative process ultimately revealed that samples, in particular geological reference materials, sharing identical petrographic or mineralogical descriptions are not necessarily chemically equivalent and can exhibit markedly different behaviors during chemical digestion procedures. These findings underscore the critical importance of continuous hypothesis testing, self-falsification, and experimental verification in scientific research, particularly when working with reference materials assumed to be identical. I will be presenting data on the analysis of platinum group elements (PGE) and osmium isotopes in geological reference materials (chromitites, ultramafic rocks and basalts), which demonstrates the need for challenging matrices for method validation. 

How to cite: Meisel, T. C.: Self-falsification as a driver of scientific progress: Insights from long-term experimental research, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5771, https://doi.org/10.5194/egusphere-egu26-5771, 2026.

In atmospheric sciences, a central tool to test hypotheses are numerical models, which aim to represent (part of) our environment. One such model is the weather and climate model ICON [1], which solves the Navier-Stokes equation for capturing the dynamics and parameterizes subgrid-scale processes, such as radiation, cloud microphysics, and aerosol processes. Specifically, for the latter exists the so-called Hamburg Aerosol Module (HAM [2]), which is coupled to ICON [3] and predicts the evolution of aerosol populations using two moments (mass mixing ratio and number concentration). The high complexity of aerosols is reflected in the number of aerosol species (total of 5), number of modes (total of 4), and their mixing state and solubility. The module calculates aerosol composition and number concentration, their optical properties, their sources and sinks, and their interactions with clouds via microphysical processes. Aerosol emissions are sector-specific and based on global emission inventories or dynamically computed.

Within our work, we stumbled upon an interesting pattern occurrence in our simulations upon changing/turning off single emission sectors. If we, e.g., removed black carbon from aircraft emissions, the strongest changes emerged over the African continent, which is not the region where we were expecting to see the strongest response. Further investigations revealed that this pattern emerges independently of the emission sector as well as species, confirming our suspicion that we are facing a bug within HAM. Here, we want to present how we approached the challenge of identifying and tackling a bug within a complex module with several thousand lines of code.

[1] G. Zängl, D. Reinert, P. Ripodas, and M. Baldauf, “The ICON (ICOsahedral Non-hydrostatic) modelling framework of DWD and MPI-M: Description of the non-hydrostatic dynamical core,” Quarterly Journal of the Royal Meteorological Society, vol. 141, no. 687, pp. 563–579, 2015, ISSN: 1477-870X. DOI: 10.1002/qj.2378

[2] P. Stier, J. Feichter, S. Kinne, S. Kloster, E. Vignati, J. Wilson, L. Ganzeveld, I. Tegen, M. Werner, Y. Balkanski, M. Schulz, O. Boucher, A. Minikin, and A. Petzold, “The aerosol-climate model ECHAM5-HAM,” Atmospheric Chemistry and Physics, 2005. DOI: 10.5194/acp-5-1125-2005

[3] M. Salzmann, S. Ferrachat, C. Tully, S. M¨ unch, D. Watson-Parris, D. Neubauer, C. Siegenthaler-Le Drian, S. Rast, B. Heinold, T. Crueger, R. Brokopf, J. Mülmenstädt, J. Quaas, H. Wan, K. Zhang, U. Lohmann, P. Stier, and I. Tegen, “The Global Atmosphere-aerosol Model ICON-A-HAM2.3–Initial Model Evaluation and Effects of Radiation Balance Tuning on Aerosol Optical Thickness,” Journal of Advances in Modeling Earth Systems, vol. 14, no. 4,e2021MS002699, 2022, ISSN: 1942-2466. DOI: 10.1029/2021MS002699

How to cite: Omanovic, N., Ferrachat, S., and Lohmann, U.: Back to square one (again and again): Finding a bug in a complex global atmospheric model  , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6794, https://doi.org/10.5194/egusphere-egu26-6794, 2026.

In situ cloud measurements are essential for understanding atmospheric processes and establishing a reliable ground truth. Obtaining these data is rarely straightforward. Challenges range from accessing clouds in the first place to ensuring that the instrument or environment does not bias the sample. This contribution explores several blunders and unexpected glitches encountered over fifteen years of field campaigns.

I will share stories of mountain top observations where blowing snow was measured instead of cloud ice crystals and the ambitious but failed attempt to use motorized paragliders for sampling. I also reflect on winter campaigns where the primary obstacles were flooding and mud rather than cold and snow. While these experiences were often frustrating, they frequently yielded useful data or led to new insights. One such example is the realization that drone icing is not just a crash risk but can also serve as a method for measuring liquid water content. By highlighting these setbacks and the successful data that emerged despite them, I aim to foster a discussion on the value of trial and error and persistence in atmospheric physics.

How to cite: Henneberger, J.: How Not to Measure a Cloud: Lessons from Fifteen Years of Fieldwork Failures, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8228, https://doi.org/10.5194/egusphere-egu26-8228, 2026.

Forests are powerful climate regulators: Their CO₂ uptake provides a global biogeochemical cooling effect, and in the tropics, this cooling is further strengthened by evapotranspiration. Given that temperature-related mortality is a relevant global health burden, which is expected to increase under climate change, we set out to test what we thought was a promising hypothesis: Can forests reduce human temperature-related mortality from climate change? 

To test this, we used simulated temperature changes to reforestation from six different Earth System Models (ESMs) under a future high-emission scenario, and paired them with age-specific population data and three methodologically different temperature-mortality frameworks (Cromar et al. 2022, Lee et al. 2019, and Carleton et al. 2022). We expected to find a plausible range of temperature-related mortality outcomes attributable to global future forests conservation efforts.

Instead, our idea ran head-first into a messy reality. Firstly, rather than showing a clear consensus, the ESMs produced a wide range of temperature responses to reforestation, varying both in magnitude and sign. This is likely due to the albedo effect, varying climatological tree cover and land use processes implemented by the models, in addition to internal variability which we could not reduce due to the existence of only one ensemble member per model. Consequently, the models disagreed in many regions on whether global forest conservation and reforestation would increase or decrease temperature by the end of the century.

The uncertainties deepened when we incorporated the mortality data. Mortality estimates varied by up to a factor of 10 depending on the ESM and mortality framework used. Therefore, in the end, the models could not even agree on whether forests increased or decreased temperature-related mortality. We found ourselves with a pipeline that amplified uncertainties of both the ESM and mortality datasets.

For now, the question remains wide open: Do trees save us from temperature-related deaths in a warming world, and if so, by how much?

* The first two authors contributed equally to this work.

How to cite: Hohmuth, N., Fahrenbach (presenting), N. L. S., Zou (presenting), Y., Reek, J., Specker, F., Crowther, T., and Zohner, C. M.: Do trees save lives under climate change? It’s complicated , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8359, https://doi.org/10.5194/egusphere-egu26-8359, 2026.

Hydrological modelling has long been shaped by a steady drive toward ever more sophisticated models. In the era of machine learning, this race has turned into a relentless pursuit of complexity: deeper networks and ever more elaborate architectures that often feel outdated by the time the ink on the paper is dry. Motivated by a genuine belief in methodological progress, I, like many others, spent considerable effort exploring this direction, driven by the assumption that finding the “right” architecture or model would inevitably lead to better performance. This talk is a reflection on that journey; you could say my own Leidensweg. Over several years, together with excellent collaborators, I explored a wide range of state-of-the-art deep-learning approaches for rainfall–runoff modelling and other hydrological modelling challenges. Yet, regardless of the architecture or training strategy, I repeatedly encountered the same performance ceiling. In parallel, the literature appeared to tell a different story, with “new” models regularly claiming improvements over established baselines. A closer inspection, however, revealed that rigorous and standardized benchmarking is far from common practice in hydrology, making it difficult to disentangle genuine progress from artefacts of experimental design. What initially felt like a failure to improve my models turned out to be a confrontation with reality. The limiting factor was not the architecture, but the problem itself. We have reached a point where predictive skill is increasingly bounded by the information content of our benchmark datasets and maybe more importantly by the way we frame our modelling challenges, rather than by model design. Like many others, I have come to believe that if we want to move beyond the current performance plateau, the next breakthroughs are unlikely to come from ever more complex models alone. Instead, as a community, we need well-designed model challenges, better benchmarks, and datasets that meaningfully expand the information available to our models to make model comparisons more informative.

How to cite: Loritz, R., Dolich, A., and Heudorfer, B.: The empty mine: Why better tools do not help you find new diamonds, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10401, https://doi.org/10.5194/egusphere-egu26-10401, 2026.

Examining catchment response to precipitation at event scale is useful for understanding how various hydrological systems store and release water. Many of such event scale characteristics, for example event runoff coefficient and event time scale are also important engineering metrics used for design. However, deriving these characteristics requires identification of discrete precipitation-streamflow events from continuous hydrometeorological time series.

Event identification is not at all a trivial task. It becomes even more challenging when working with very large datasets that encompass a wide range of spatial and temporal dynamics. Approaches range from visual expert judgement to baseflow-separation-based methods and objective methods based on the coupled dynamics of precipitation and streamflow. Here, we would like to present our experience in the quest to devise the “ideal” method for large datasets – and trust us, we tried, a lot. We demonstrate that expert-based methods can be seriously flawed simply by changing a few meta parameters, such as the length of displayed periods, baseflow-separation-based methods deliver completely opposite results when different underlying separation methods are selected, and objective methods suddenly fail when dynamics with different temporal scales are simultaneously present.

Ultimately, we realized that finding a one-size-fits-all method was not possible and that compromises had to be made to select sufficiently representative events across large datasets. Therefore, we advocate for pragmatic case-specific evaluation criteria and for transparency in event identification to make study results reproducible and fit for purpose, if not perfect.

How to cite: Tarasova, L. and Astagneau, P.: How NOT to identify streamflow events?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13630, https://doi.org/10.5194/egusphere-egu26-13630, 2026.

A defining attribute of global-storm resolving models is that modelling is replaced by simulation.  In addition to overloading the word “model”  this avails the developer of a much larger variety of tests, and brings about a richer interplay with their intuition.  This has proven helpful in identifying and correcting many mistakes in global-storm resolving models that traditional climate models find difficult to identify, and usually compensate by “tuning.”  It also means that storm-resolving models are built and tested in a fundamentally different way than are traditional climate models. In this talk I will review the development of ICON as a global storm resolving model to illustrate how this feature, of trying to simulate rather than model the climate system, has helped identify a large number of long-standing bugs in code bases inherited from traditional models; how this can support open development; and how sometimes these advantages also prove to be buggy.

How to cite: Stevens, B., Giorgetta, M., and Segura, H.: Buggy benefits of more fundamental climate models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14148, https://doi.org/10.5194/egusphere-egu26-14148, 2026.

Hydrological and water systems modelling has long been driven by the search for better models. We do so by searching for models or at least parameter combinations that provide the best fit to given observations. We ourselves have contributed to this effort by developing new methods and by publishing diverse case studies. However, we repeatedly find that searching for and finding an optimal model is highly fraught in the presence of unclear signal-to-noise ratios in our observations, of incomplete models and of highly imbalanced databases. We present examples of our own work through which we have realized that achieving optimality was possible but futile unless we give equal consideration to issues of consistency, robustness and problem framing. We argue here that the strong focus on optimality continues to be a hindrance for advancing hydrologic science and for transferring research achievements into practice – probably more so than in other areas of the geosciences.

How to cite: Wagener, T. and Pianosi, F.: The dangerous temptation of optimality in hydrological and water resources modelling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14374, https://doi.org/10.5194/egusphere-egu26-14374, 2026.

Among soil physical analyses, determination of the soil particle-size distribution (PSD) is arguably the most fundamental. The standard methodology combines sieve analysis for sand fractions with sedimentation-based techniques for silt and clay. Established sedimentation methods include the pipette and hydrometer techniques. More recently, the Integral Suspension Pressure (ISP) method has become available, which derives PSD by inverse modeling of the temporal evolution of suspension pressure measured at a fixed depth in a sedimentation cylinder. Since ISP is based on the same physical principles as the pipette and hydrometer methods, their results should, in principle, agree.

The ISP methodology has been implemented in the commercial instrument PARIO (METER Group, Munich). While elegant, the method relies on pressure change measurements with a resolution of 0.1 Pa (equivalent to 0.01 mm of water column). Consequently, the PARIO manual strongly advises avoiding any mechanical disturbance such as thumping, bumping, clapping, vibration, or other shock events. This warning is essentially precautionary, because to date no systematic experimental investigation of such disturbances has been reported.

To explore this issue, we prepared a single 30 g soil sample following standard PSD procedures and subjected it to 26 PARIO repeated measurement runs over a period of five months, each run lasting 12 h. Between runs, the suspension was remixed but otherwise not altered. The first ten runs (over ten days) were conducted without intentional disturbance to establish baseline repeatability. This was followed by eight runs with deliberately imposed and timed disturbances that generated single or repeated vibrations (“rocking and shocking”). After approximately two and five months, we conducted additional sets of five and three undisturbed runs, respectively.

We report how these mechanical disturbances, along with temperature variations during measurement and the time elapsed since sample pre-treatment, affected the derived PSD. The results provide a first quantitative assessment of how fragile—or robust—the ISP method and PARIO system really are when reality refuses to sit perfectly still.

How to cite: Nemes, A. and Durner, W.: Rocking and Shocking the PARIOTM: How Sensitive Is ISP-Based Particle-Size Analysis to Mechanical Disturbance?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14763, https://doi.org/10.5194/egusphere-egu26-14763, 2026.

Predicting soil hydraulic behavior is necessary for the modeling of catchments and agricultural planning, particularly for a country like Norway where only 3% of land is suitable for farming. Soil texture is an important and easily accessible parameter for the prediction of soil hydraulic behavior. However, some Norwegian farmland soils, which formed as glacio-marine sediments and are characterized by a medium texture, have shown the hydraulic behavior of heavy textured soils. Coined by the theory behind well-established sedimentation-enhancing technology used in waste water treatment, we hypothesized that sedimentation under marine conditions may result in specific particle sorting and as a result specific pore system characteristics. To test this, we designed four custom-built devices to produce artificially re-sedimented columns of soil material to help characterize the influence of sedimentation conditions. We successfully produced column samples of the same homogeneous mixture of fine-sand, silt, and clay particles obtained by physically crushing and sieving (< 200 µm) subsoil material collected at the Skuterud catchment in South-East Norway, differing only in sedimentation conditions (deionized water vs 35 g per liter NaCl solution). Then, the inability of standard laboratory methods to measure the saturated hydraulic conductivity of such fine material, led us to “MacGyver” (design and custom-build) two alternative methodologies to measure that property, i.e. i) by adapting a pressure plate extractor for a constant head measurement and ii) by building a 10 m tall pipe-system in a common open area of the office, in order to increase the hydraulic head on the samples. There was a learning curve with both of those methods, but we have found that the salt-water re-sedimented columns were about five times more permeable than the freshwater ones, which was the complete opposite of our expectations. However, an unexpected blunder in the conservation of our samples suggests that our hypothesis should be further explored rather than dismissed. These contributions hint about the mechanisms that may underlie the anomalous hydraulic behaviour of certain Norwegian soils and raise new questions on the formation of marine clays, improving knowledge available for land managers and modellers.

How to cite: Nemes, A., Bazzocchi, P., Weiland, S., and van der Ploeg, M.: Some Norwegian soils behave differently: is it an inheritance from marine sedimentation?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14852, https://doi.org/10.5194/egusphere-egu26-14852, 2026.

“It is in the tentative stage that the affections enter with their blinding influence. Love was long since represented as blind…The moment one has offered an original explanation for a phenomenon which seems satisfactory, that moment affection for his intellectual child springs into existence…To guard against this, the method of multiple working hypotheses is urged. … The effort is to bring up into view every rational explanation of new phenomena, and to develop every tenable hypothesis respecting their cause and history. The investigator thus becomes the parent of a family of hypothesis: and, by his parental relation to all, he is forbidden to fasten his affections unduly upon any one” (Chamberlin, 1890).

The MADE (macro-dispersion) natural-gradient tracer field experiments were conducted more than 35 years ago. It aimed to determine field-scale dispersion parameters based on detailed hydraulic conductivity measurements to support transport simulation. A decade of field experiments produced a 30-year paper trail of modelling studies with no clear resolution of a successful simulation approach for practical use in transport problems.  As a result, accurately simulating contaminant transport in the subsurface remains a formidable challenge in hydrogeology.

What went awry, and why do we often miss the mark?

Herweijer et al. (2026) conducted a ‘back to basics’ review of the original MADE reports and concluded that there are significant inconvenient and unexplored issues that influenced the migration of the tracer plume and or biased observations. These issues include unreliable measurement of hydraulic conductivity, biased tracer concentrations, and underestimation of sedimentological heterogeneity and non-stationarity of the flow field. Many studies simulating the tracer plumes appeared to have ignored, sidestepped, or been unaware of these issues, raising doubts about the validity of the results.

Our analysis shows that there is a persistent drive among researchers to conceptually oversimplify natural complexity to enable testing of single-method modelling, mostly driven by parametric stochastic approaches. Researchers tend to be anchored to a specialised, numerically driven methodology and have difficulty in unearthing highly relevant information from ‘unknown known’ data or applying approaches outside their own specialised scientific sub-discipline. Another important aspect of these ‘unkowns knowns’ is the tendency to accept published data verbatim. Too often, there is no rigorous investigation of the original measurement methods and reporting, and, if need be, additional testing to examine the root cause of data issues.

Following the good old advice of Chamberlin (1890), we used a knowledge framework to systematically assess knowns, unknowns, and associated confidence levels, yielding a set of multi-conceptual models. Based on identified 'unknowns', these multi-models can be tested against reliable 'knowns' such as piezometric data and mass balance calculations.  

Chamberlin, T.C., 1890, The method of multiple working hypotheses. Science 15(366): 92-96. doi:10.1126/science.ns-15.366.92.

Herweijer J.C., S. C Young, P. Hayes, and O. Batelaan, 2026, A multi-conceptual model approach to untangling the MADE experiment, Accepted for Publication in Groundwater.

How to cite: Batelaan, O., Herweijer, J., Young, S., and Hayes, P.: The unknown knowns – the inconvenient knowledge in hydrogeology we do not like to use, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16619, https://doi.org/10.5194/egusphere-egu26-16619, 2026.

Free-slip boundary conditions are routinely used in 3D geodynamic modelling because they reduce computational cost, avoid artificial shear zones at domain edges, and simplify the implementation of large-scale kinematic forcing. However, despite their apparent neutrality, our experiments show that free-slip boundaries systematically generate first-order artefacts that propagate deep into the model interior and can severely distort the interpretation of continental rifting simulations.

Here we present a set of 3D visco-plastic models inspired by the South China Sea (SCS) that were originally designed to study the effect of steady-state thermal inheritance and pluton-controlled crustal weakening. Unexpectedly, in all simulations except those with a very particular inverted rheological profile (POLC), the free-slip boundary on the “Vietnam side” of the domain generated a persistent secondary propagator, producing unrealistic amounts of lithospheric thinning in the southwest corner. This artefact appeared irrespective of crustal rheology, seeding strategy, or the presence of thermal heterogeneities.

We identify three systematic behaviours induced by free-slip boundaries in 3D:
(1) forced rift nucleation at boundary-adjacent thermal gradients,
(2) artificial propagator formation that competes with the intended first-order rifting, and
(3) rotation or shearing of micro-blocks not predicted by tectonic reconstructions.

These artefacts originate from the inability of free-slip boundaries to transmit shear traction, which artificially channels deformation parallel to the boundary when lateral thermal or mechanical contrasts exist. In 3D, unlike in 2D, the combination of oblique extension and boundary-parallel velocity freedom leads to emergent pseudo-transform behaviour that is entirely numerical.

Our results highlight a key negative outcome: free-slip boundaries cannot be assumed neutral in 3D rift models, especially when studying localisation, obliquity, multi-propagator dynamics, or the competition between structural and thermal inheritance. We argue that many published 3D rift models may unknowingly include such artefacts.

How to cite: Le Pourhiet, L.: The Hidden Propagator: How Free-Slip Boundaries Corrupt 3D Simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17373, https://doi.org/10.5194/egusphere-egu26-17373, 2026.

How to cite: Williamson, E., Pritchard, M., Iwi, A., Pepler, S., and Parton, G.: Data Disaster to Data Resilience: Lessons from CEDA’s Data Recovery , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18600, https://doi.org/10.5194/egusphere-egu26-18600, 2026.

Aerosol-cloud interactions remain one of the largest uncertainties in global climate modelling. This uncertainty arises because of the dependence of aerosol-cloud interactions on many tightly coupled atmospheric processes; the non-linear response of clouds to aerosol perturbations across different regimes; and the challenge of extracting robust signals from noisy meteorological observations. The problem is particularly acute in the Arctic, where sparse observational coverage limits model constraints, pristine conditions can lead to unexpected behaviour, and key processes remain poorly understood.

A common way to tackle the challenge of uncertainties arising from aerosol-cloud interactions in climate simulations is to conduct sensitivity experiments using cloud and aerosol microphysics schemes based on different assumptions and parameterisations. By comparing these experiments, key results can be constrained by sampling the range of unavoidable structural uncertainties in the models. Here, we apply this approach to a case study of an extreme, polluted warm air mass in the Arctic that was measured during the MOSAiC Arctic expedition in 2020. We simulated the event in the WRF-Chem-Polar regional climate model both with and without the anthropogenic aerosols from the strong pollution event to study the response of clouds and surface radiative balance. To understand the sensitivity of our results to the choice of model configuration, we tested two distinct, widely-used cloud microphysics schemes.

Initial results showed that the two schemes simulated opposite cloud responses: one predicted a surface cooling from the pollution that was reasonably in line with our expectations of the event, while the other predicted the opposite behaviour in the cloud response and an associated surface warming. These opposing effects seemed to suggest that structural uncertainties in the two schemes relating to clean, Arctic conditions was so strong that it even obscured our ability to understand the overall sign of the surface radiative response to the pollution.

However, since significant model development was required to couple these two cloud microphysics schemes to the aerosol fields in our model, there was another explanation that we couldn’t rule out: a bug in the scheme that was producing the more unexpected results. In this talk, we will explore the challenges of simulating the Arctic climate with a state-of-the-art chemistry-climate model and highlight how examples like this underscore the value of our recent efforts to align our collaborative model development with software engineering principles and Open Science best practices.

How to cite: Lapere, R., Price, R., Marelle, L., Bastien, L., and Thomas, J.: Opposite cloud responses to extreme Arctic pollution: sensitivity to cloud microphysics, or a bug?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19755, https://doi.org/10.5194/egusphere-egu26-19755, 2026.

All statistical tools come with assumptions. Yet many scientists treat statistics like a collection of black-box methods without learning the assumptions. Here I illustrate this problem using dozens of studies that claim to show that solar variability is a dominant driver of climate. I find that linear regression approaches are widely misused among these studies. In particular, they often violate the assumption of ‘no autocorrelation’ of the time series used, though it is common for studies to violate several or all of the assumptions of linear regression. The misuse of statistical tools has been a common problem across all fields of science for decades. This presentation serves as an important cautionary tale for the Earth Sciences and highlights the need for better statistical education and for statistical software that automatically checks input data for assumptions.

How to cite: Steiger, N.: Pervasive violation of statistical assumptions in studies linking solar variability to climate, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19776, https://doi.org/10.5194/egusphere-egu26-19776, 2026.

A key reason for the widespread use of peat-based growth media in horticulture is their reliable nutrient availability when supplemented with fertilisers. However, due to environmental concerns over continued peat-extraction and use, peat-alternatives (e.g., coir, wood fibre, composted bark, biochar) are increasingly being used commercially. These alternative media often blend multiple materials, making it crucial to understand elemental composition and nutrient interactions between components. This study evaluates whether benchtop Energy Dispersive X-ray Fluorescence (EDXRF) can provide a rapid method for determining the elemental composition of peat-alternative components.

Representative growing media components (peat, coir, wood fibre, composted bark, biochar, horticultural lime, perlite, slow-release fertilisers, and trace-element fertiliser) were blended in different ratios to generate industry-representative mixes. Individual components and prepared mixes were dried and milled to ≤80 μm. An industry-representative mix (QC-50: 50% peat, 30% wood fibre, 10% composted bark, 10% coir, with fertiliser and lime additions) and 100% peat were analysed by EDXRF (Rigaku NEX-CG) for P, K, Mg, Ca, S, Fe, Mn, Zn, Cu and Mo, and compared against ICP-OES reference measurements. The instrument’s fundamental parameters (FP) method using a plant-based organic materials library showed large discrepancies relative to ICP-OES (relative differences: 268–390 084%) for most elements in both QC-50 and peat, with the exception of Ca in QC-50 (11%). These results confirm that the FP approach combined with loose-powder preparation is unsuitable for accurate elemental analysis of organic growing media.

An empirical calibration was subsequently developed using 18 matrix-matched standards (CRMs, in-house growing media and individual component standards). Matrix matching is challenging because mixes are mostly organic by volume, yet variable inorganic amendments (e.g., lime, fertilisers, and sometimes perlite) can strongly influence XRF absorption/enhancement effects. Calibration performance was optimised iteratively using QC-50 as the validation sample, until relative differences were <15% for all elements. When applied to 100% peat, agreement with ICP-OES results improved substantially for some macro-elements (e.g. Mg 10%, Ca 1%, S 19%) but remained poor for most trace elements (28–96%), demonstrating limited transferability of this calibration method across different elements and matrices tested.

Overall, these results demonstrate that loose powder preparation does not provide sufficiently robust accuracy for EDXRF analysis of organic growing media even with meticulous empirical matrix-matched calibration. We are therefore developing a pressed pellet method using a low-cost wax binder to improve sample homogeneity (packing density) and calibration transferability. Twenty unknown mixes will be analysed using both loose powder and pressed-pellet calibrations, and agreement with reference data (ICP-OES) will confirm method validation, supporting the development of EDXRF as a novel approach for growing media analysis.

How to cite: De Silva, T., Tupaz, C., Croffie, M., Daly, K., Gaffney, M., Stock, M., and Corbett, E.: Developing Matrix-Matched Empirical Calibrations for EDXRF Analysis of Peat-Alternative Growth Media, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20122, https://doi.org/10.5194/egusphere-egu26-20122, 2026.

In catchment hydrology, long-term data collection often starts as part of a (doctoral) research project. In some cases, the data collection continues on a limited budget, often using the field protocol and data management plan designed for the initial short-term project. Challenges and issues with the continued data collection are likely to arise, especially when there are multiple changes in the people involved. It is especially difficult for researchers who were not directly involved in the fieldwork to understand the data and must therefore rely on field notes and archived data. They then often encounter issues related to inconsistent metadata, such as inconsistent date-time formats and inconsistent or missing units, missing calibration files, and unclear file and processing script organization.

While the specific issues may sound very case-dependent, based on our own and other’s experiences from various research projects, it appears that many issues recur more frequently than one might expect (or be willing to admit). In this presentation, we will share our experiences with bringing spatially distributed groundwater level data collected in Sweden and Switzerland from the field to ready-to-use files. Additionally, we provide recommendations for overcoming the challenges during field data collection, data organization, documentation, and data processing using scripts. These include having a clear, detailed protocol for in the fieldwork and the data processing steps, and ensuring it is followed. Although protocols are often used, they are frequently not detailed enough or are not used as designed. The protocols might also not take into account the further use of the data, such as for hydrological modelling, beyond field collection. 

How to cite: Bremer, K., Staudinger, M., Seibert, J., and van Meerveld, I.: From Field to File: challenges and recommendations for handling hydrological data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20375, https://doi.org/10.5194/egusphere-egu26-20375, 2026.

In 2014 we developed the Wageningen Lowland Runoff Simulator (WALRUS), a conceptual rainfall-runoff model for catchments with shallow groundwater. Water managers and consultants were involved in model development. In addition, they sponsored the steps necessary for application: making an R package, user manual and tutorial, publishing these on GitHub and organising user days. WALRUS is now used operationally by several Dutch water authorities and for scientific studies in the Netherlands and abroad. When developing the model, we made certain design choices. Now, after twelve years of application in water management, science and education, we re-evaluate the consequences of those choices.

The lessons can be divided into things we learned about the model’s functioning and things we learned from how people use the model. Concerning the model’s functioning, we found that keeping the model representation close to reality has advantages and disadvantages. It makes it easy to understand what happens and why, but it also causes unrealistic expectations. Certain physically based relations hampered model performance because they contained thresholds, and deriving parameter values from field observations resulted in uncertainty and discussions about spatial representativeness.

Concerning the practical use, we found that the easy-to-use, open source R package with manual was indispensable for new users. Nearly all users preferred default options over the implemented user-defined functions to allow tailor-made solutions. Parameter calibration was more difficult than expected because the feedbacks necessary to simulate the hydrological processes in lowlands increase the risk of equifinality. In addition, lack of suitable discharge data for calibration prompted the request for default parameter values. Finally, the model was subject to unintended model use, sometimes violating basic assumptions and sometimes showing unique opportunities we had not thought of ourselves.

C.C. Brauer, A.J. Teuling, P.J.J.F. Torfs, R. Uijlenhoet (2014): The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater, Geosci. Model Dev., 7, 2313-2332, doi:10.5194/gmd-7-2313-2014

How to cite: Brauer, C.: Re-evaluating the WALRUS rainfall-runoff model design after twelve years of application, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21915, https://doi.org/10.5194/egusphere-egu26-21915, 2026.

Using a new global seismological analysis technique designed to detect long-lasting coherent signals, we identify both previously known and entirely unrecognized resonant-like seismic emissions at periods longer than 10 seconds. A detailed examination of these signals allows us to locate their sources with remarkable precision. Strikingly, they cluster in offshore sedimentary basins near major river fans and beneath ice-covered regions. Although their resonant character resembles classic volcanic tremor, the source locations indicate that they are not associated with any known volcanic system.

A careful analysis of their frequency content, spatial distribution, and radiation patterns instead suggests that these signals may originate from the resonance of fluids within shallow subsurface reservoirs. This interpretation aligns with the presence of large volumes of gas, oil, and water in thick sedimentary basins, and with seafloor seepage structures that release substantial amounts of naturally generated fluids from depths of roughly 5–10 km.

By tracking the temporal evolution of these signals, we also identify a pronounced seasonal modulation that mirrors oceanic variability. This observation points to a significant coupling between the oceans and the solid Earth, potentially mediated by static or dynamic stress transfer.

The detection of these newly recognized signals opens a promising path toward probing the largely unexplored dynamics of sedimentary layers and their sensitivity to external environmental forcing. More broadly, these findings introduce a new class of geophysical observables capable of revealing how the shallow lithosphere responds to, and interacts with, oceanic processes on seasonal to long-term timescales.

How to cite: Poli, P. and Takano, T.: Detection and characterization of resonant signals in global seismology: Evidence for shallow fluid reservoirs and their interaction with the oceans, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1453, https://doi.org/10.5194/egusphere-egu26-1453, 2026.

Monitoring dynamic surface processes such as sediment transport and turbulence during high-flow events remains a major challenge in fluvial geomorphology. Seismic methods provide a non-invasive alternative, but robust source localisation is challenged by the distributed nature of fluvial sources, heterogeneous shallow structures, and the broadband character of the signals they produce. Because turbulence and bedload dominate different parts of the spectrum, we require broadband analysis. We establish a generalised framework for frequency-resolved seismic source localisation using dense arrays and matched field processing. We introduce a hybrid processing strategy that exploits the array differently across frequencies: full-network matched field processing at low frequencies, where coherence spans the entire aperture, and sub-array averaging at higher frequencies, where coherence is confined to local scales. We apply the framework to a field case, where we retrieve frequency-dependent source regions across the active channel and separate low-frequency turbulent noise from higher-frequency bedload impacts. We conduct synthetic tests to quantify localisation uncertainty as a function of frequency, sensor density, and signal-to-noise ratio. Across the 2-40 Hz range, we find that localisation uncertainty varies from a few metres at low frequencies to more than 100 m at high frequencies, reflecting the expected loss of resolution at shorter wavelengths. By quantifying these trade-offs, we provide practical guidance for future deployments, including sensor spacing and array geometry required to achieve a target resolution.

How to cite: Venkatesh Revankar, S., Gimbert, F., and Recking, A.: Frequency-Resolved Seismic Source Localization in Fluvial Settings Using Dense Arrays, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4482, https://doi.org/10.5194/egusphere-egu26-4482, 2026.

High-frequency acoustic and seismic signals generated by granular flows, such as bedload transport and debris flows, provide valuable information on sediment dynamics, yet the physical interpretation remains challenging. In dense or partially dense solid-fluid granular flows, signal generation is controlled not only by particle-bed impacts but also by frequent inter-particle collisions within the actively shearing layer. These collisions are shear-driven and evolve rapidly in time and space, with impact rates being highly sensitive to shear strain rate, time, and granular layer thickness. However, most existing particle impact rate models assume stationary conditions and neglect the spatiotemporal variability inherent in natural geophysical flows, limiting the ability to explain observed non-stationary spectral signatures. Here, we develop a new analytical framework for particle impact rate in solid-fluid two-phase granular flows based on non-equilibrium thermodynamics. The model explicitly links collision rate to shear strain rate, granular state variables, and the thickness of the basal shearing layer, allowing impact rates to evolve dynamically in time and space. Reformulating the model in the frequency domain provides a direct theoretical connection between evolving collision rates and the spectral properties of the generated acoustic and seismic signals. For saturated channel beds, we further investigate the two-way coupling between pore water pressure and particle impacts in signal generation. Particle impacts are conceptualized as transient mechanical sources that locally compact the granular skeleton, reduce pore volume, and generate excess pore pressure, which in turn feeds back on particle impacts. Analytical solutions demonstrate that the amplitude and persistence of impact-induced pore pressure perturbations are controlled by bed permeability, shear strain rate, and the thickness of the basal shear layer. An increase in pore pressure reduces effective stress and feeds back on collision dynamics, introducing an additional control on signal generation. Building on these results, we extend existing power spectral density formulations to show that temporally evolving particle impact rates modulate frequency spectra by redistributing spectral power across frequences, resulting in departures from classical spectral scaling. Pore pressure effects further modify spectral amplitudes and attenuation. The proposed framework offers new physical insights into sediment-generated signals, enabling improved interpretation of evolving particle impact rates and pore pressure related effects in bedload transport and debris flows.

How to cite: Chen, Z., Rickenmann, D., Walter, F., McArdell, B., Kang, J., Wetter, C., and Badoux, A.: Spatiotemporally evolving particle impact rates in sediment-generated acoustic signals, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5278, https://doi.org/10.5194/egusphere-egu26-5278, 2026.

Fluvial seismology is an emerging field that exploits seismic signals generated by fluvial processes to monitor bedload transport and flow turbulence. Currently, most previous studies have focused on small mountain rivers, while seismic signatures from large rivers remain poorly explored. The Tiger Leaping Gorge is a deeply incised, narrow gorge in the upper Yangtze River characterized by extreme topographic relief and intense fluvial incision. Over a river length of approximately 20 km, the riverbed elevation drops by ~200 m, and the maximum discharge can reach ~5000 m³ s⁻¹, making the gorge an exceptional natural laboratory for investigating the coupling between seismic signals and hydrodynamic processes in large rivers. Until March 2022, we deployed 35 seismic stations along the riverbanks of the Tiger Leaping Gorge to continuously monitor the actively incising river segment.

We analyzed eight months of continuous seismic data along the river channel. In contrast to observations from small rivers, we identify two distinct and well-separated seismic energy bands at most stations. Temporal variations in both frequency bands show strong correlations with river discharge. We interpret the higher-frequency energy band as being primarily generated by small-scale eddy interacting with a rough riverbed, a process that appears to be particularly pronounced in large rivers. Building on existing models of turbulence-generated and bedload-generated seismic signals, we further tested different inversion approaches and applied them to all stations in the array. This allowed us to reconstruct the spatiotemporal variations in river stage and bedload transport across the study area.

Our results reveal that large rivers exhibit seismic signal characteristics controlled by distinct flow-related mechanisms, a phenomenon that has not been fully recognized in previous studies of small-scale rivers. Moreover, this study demonstrates that dense seismic arrays can resolve river dynamic processes at high spatial and temporal resolution, highlighting the potential of fluvial seismology for monitoring large river systems.

How to cite: Yan, X., Tang, H., Liu-Zeng, J., Turowski, J., Wang, Y., Yang, J., Wang, J., and Zhou, Q.: Seismic signatures of large river dynamics revealed by a dense seismic array at the Tiger Leaping Gorge of the Jinsha River, SE Tibet, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6957, https://doi.org/10.5194/egusphere-egu26-6957, 2026.

In mountain catchments, floods can mobilize large amounts of sediment, yet monitoring these events remains a major challenge. Understanding the processes governing sediment transport during extreme floods, such as flood waves and sediment pulses, is key to improving our understanding of rapid erosion dynamics. Environmental seismology offers a powerful approach to detect and quantify these processes remotely and continuously with high temporal resolution.

The Mediterranean basin is characterized by a climate and topography prone to flash floods. The objective of this work is to quantify the sediment transport that occurred during the extreme flooding associated with Storm Alex (October 2020), and the subsequent major flood caused by Storm Aline (October 2023), on the Roya River in southeast France.

To address this objective, we use seismic measurements from a single-component geophone (natural frequency of 4.5 Hz) installed at 5 m from the Roya River. We apply previously developed physical models describing the seismic power generated by river bedload transport (saltation model) and turbulent flow. Comparison with model predictions suggests that, at such short distances, the recorded seismic power is dominated by the bedload process, allowing us to focus on the saltation model.

To quantify the sediment transport during periods of peak seismic amplitude, we calibrate the parameters of the saltation model to the Roya River context. Although the resulting volumetric sediment flux is consistent in order of magnitude with theoretical and empirical estimates, the complexity of the physical environment calls for further investigation. Seismic parameters of the riverbed, realistic grain size distributions of transported sediments, and local hydrometric data remain difficult to constrain directly. We address these uncertainties through sensitivity analyses, which show that seismic medium parameters mainly control the shape of the seismic spectrum. We therefore explore the use of real data that we obtain from an active and passive seismic experiment to adjust those parameters

Water depth is another key parameter of the saltation model, as it controls the basal shear stress. We estimate flow depth using upstream discharge measurements and local discharge modeling with simplified theoretical relationships between flow depth, river width, and discharge. Ongoing and future work includes seismic array measurements and local hydraulic modelling to further constrain model parameters. Overall, our results highlight the potential of environmental seismology to quantify sediment transport during extreme flash floods and to improve process-based understanding of sediment transfer in steep Mediterranean river systems.

How to cite: Dib, M.-O., Chmiel, M., Chapuis, M., Ampuero, J.-P., Abily, M., Mercerat, D., and Courboulex, F.: Seismic monitoring of sediment transport during flash floods:  Case studies of Storms Alex and Aline on the Roya river, France, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9430, https://doi.org/10.5194/egusphere-egu26-9430, 2026.

Surge-type debris flows advance through successive surges, during which in-channel deposition layers progressively develop between surges and continuously modify basal conditions. Seismic observations from Jiangjia Ravine show that ground vibration amplitudes systematically weaken as surge sequences evolve, even when successive surges exhibit similar flow magnitudes, implying a breakdown in the conventional scaling between flow intensity and seismic response. This phenomenon is interpreted as a consequence of the progressive buildup and partial liquefaction of inter-surge deposition layers, rather than the influence of static, pre-existing bed deposits. To represent this process quantitatively, we introduce an effective transmission parameter (ξ) into a fluvial seismology framework and establish a sigmoid relationship between ξ and the normalized thickness of the deposition layer (H*). Incorporating this relationship substantially enhances the ability to reproduce observed variations in seismic power spectral density (PSD) across surge sequences and offers a transferable means of capturing subsurface flow–bed coupling. These results highlight the importance of dynamic bed evolution in controlling debris-flow-generated seismic signals and provide new insights for improving real-time monitoring and early-warning strategies in sediment-laden mountain catchments.

How to cite: Jiang, F. and Song, D.: Liquefied Deposition Layers Modulate Seismic Wave Propagation in Surge-type Debris Flows, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9446, https://doi.org/10.5194/egusphere-egu26-9446, 2026.

Near-surface groundwater dynamics (NSGD) reflect residence and recharge of the terrestrial water and control the water resource of the downstream area. Environmental seismology, using seismic velocity changes (dv/v), provides a non-invasive approach to observe NSGD. Here, we use ambient seismic noise at four seismic stations, hydraulic, and meteorological records from the Liwu watershed, Taiwan, following Typhoon Kompasu in 2021 to investigate NSGD in response to typhoon rainfall. We used the single-station cross-component (SC) method to construct daily correlation functions, and dv/v was computed by the stretching method in the frequency band of 4–8 Hz. Moreover, we simulated dv/v using a near-surface layer of limited storage capacity and adjusted hydraulic conductivity (Ks). Our results indicate that peak dv/v at the downstream station was about four times that at the divide, with recovery to pre-typhoon levels taking 29 days, compared to 8 days at the divide station. Simulated Ks shows that hydraulic conductivity values higher than borehole-derived estimates are required to best capture the observed dv/v responses, indicating the preferential flow may be via colluvium and fractured bedrock in the study site. In short, a five-day typhoon produced nearly one month of NSGD, demonstrating that near-surface groundwater may function as a temporary storage zone for deep groundwater. These results demonstrate that ambient seismic noise can resolve short-term subsurface water dynamics during extreme events, offering new constraints on water residence times and aquifer structure that are relevant for disaster management and biogeochemical studies in mountainous watersheds.

How to cite: Tsai, C.-H., Yang, C., Illien, L., and Chen, L.-W.: Typhoon-driven Near-surface Groundwater Dynamics Revealed by Ambient Noise in the Mountain Watershed, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9607, https://doi.org/10.5194/egusphere-egu26-9607, 2026.

The manner by which glaciers evacuate the products of erosion is poorly known, especially for the coarser-sized sediments produced by plucking and quarrying, that is the bedload fraction. It has traditionally been assumed that bedload export from Alpine glaciers is relatively efficient. However, continuous, seismic measurements of bedload transport at glacier portals question this assumption as do the results of numerical modelling experiments. There are a number of possible hypotheses to explain such inefficiency, including the structure and geometry of subglacial channels, periodic variation in discharge due to diurnal melt cycles and near-ice margin effects. The problem remains, however, that there are no published datasets on subglacial bedload transport to investigate the effects, not surprising because of the challenges associated with measuring it. The aim of this research is to harness environmental seismology to quantify subglacial bedload transport rates for the first time using on-ice measurements.

In the first part of the project, we traced the location and development of two subglacial channels of Glacier d’Otemma, Valais, Switzerland. In this study, we investigate the discharge and sediment traveling in our identified channels. With the help of thirty seismic sensors on the glacier surface and at the glacial terminus, we record the seismic activity of Glacier d’Otemma during its melt season in 2024. We trace the path the sediment takes underneath the glacier with seismic beamforming techniques and relate it to the previously identified shape of the subglacial drainage system. A line of seismic sensors along the glacier was able to record waves of bedload as they travel underneath the ice. With the help of physical models, the spectral information of the ground motion data is translated into sediment transport and discharge quantities. The project contributes to reveal the interaction of sediment and the characteristics of subglacial drainage system in alpine glaciers, giving further insights into erosion mechanisms at play.

How to cite: Wolf, E., Mancini, D., Dietze, M., Stutzmann, E., Metaxian, J.-P., and Lane, S.:  Observing subglacial bedload transport dynamics with on-ice seismic networks on Glacier d’Otemma, Switzerland, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9649, https://doi.org/10.5194/egusphere-egu26-9649, 2026.

Long-term seismic monitoring provides a unique insight into glacier and ice-shelf dynamics. However, the extraction of meaningful cryoseismic information from continuous multi-year records remains challenging. Icequake events frequently show unclear or overlapping signals due to harsh environmental conditions and persistent background activity. While the utilisation of variable event lengths can be instrumental in the avoidance of merging multiple events into a single window, most unsupervised learning methods require fixed input durations. This emphasises the necessity for a novel unsupervised clustering approach that can handle time-variant events of varying lengths while robustly detecting outliers. The method should be physics-based to accommodate the limited prior knowledge of icequake characteristics. It should also operate directly on large event catalogues, without reliance on handcrafted features.

To address this issue, the incrementally buffered dynamic time warping clustering is introduced. This is a new approach to clustering dynamic time warping (DTW) distances of events and it incorporates the requirements stated above. The method starts with an initial k-medoids clustering on a pairwise DTW distance matrix of a subset of events, thereby generating initial k clusters. The subsequent addition of new samples is based on a statistically robust distance threshold from the distribution in within-cluster distances of the initial step. Each event is compared only to existing medoids, assigned to the nearest cluster if the DTW distance falls below the threshold, or temporarily placed in a buffer when classified as an outlier. The promotion of buffered events to new clusters is only permitted when the criteria for similarity and minimum sample count are met, thus preventing the formation of spurious clusters from isolated noise events. Lastly, a final global reassignment step is performed. This step involves the recomputation of all event-to-medoid distances. The purpose of this is to stabilise cluster boundaries and refine the catalogue. The combination of these steps results in a scalable and transparent algorithm that is well-suited to the analysis of extensive environmental time-series data.

The present study applies this framework to a time span of several years of vertical-component seismic data from the 16-sensor Watzmann array at Neumayer Station III, Antarctica. Preliminary results indicate the presence of numerous persistent families of icequakes. These are analysed with regard to their correlation with environmental conditions, including tidal modulation and wind.

How to cite: Kiel, A., Hammer, C., and Schlindwein, V.: A Robust Framework for Clustering Variable-Length Seismic Events: A Cryogenic Case Study , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9781, https://doi.org/10.5194/egusphere-egu26-9781, 2026.

Atmospheric effects, specifically wind and precipitation, are often considered as dominant sources of noise in seismic records, both in the high frequency and ultra low frequency domain. However, those two processes are also important drivers of geomorphic activity: wind causing advective processes, aeolian transport and erosion, tree uprooting, and energy transfer from the atmosphere to the ground. Precipitation, specifically rain, controls splash erosion, surface sealing through puddling, soil moisture, groundwater fluctuations, and importantly, the initiation of surface flow and resulting flood and sediment transport waves. Despite their widespread reflection in seismic data sets, especially in the context of environmental seismology studies, there is surprisingly little valorisation of the signal content associated with these two environmental variables. Here, I show case study based examples of the different signatures of wind and rain in seismic data sets to illustrate the systematic variability arising from different process modes, intensities and types of interaction with elements of the Critical Zone. I make use of physical models of rainfall and modified models of wind interaction with open ground and trees, to explore the information that can be extracted from seismic data sets by inverting those models in combination.

How to cite: Dietze, M.: Surveying and modelling the distributed effects of wind and rain, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10606, https://doi.org/10.5194/egusphere-egu26-10606, 2026.

Quantifying the source levels and localizing blue whale vocalizations in the Gulf of St. Lawrence is essential for effective management of this endangered population in a region of intense shipping activity. We present an innovative study leveraging data from diverse observational platforms, i.e., ocean bottom seismometers and underwater gliders. Since 2019, gliders equipped with hydrophones have been deployed every summer in the Honguedo Strait shipping lane between Gaspé and Anticosti Island, in the Gulf of St. Lawrence, to trigger mitigation measures when detecting North Atlantic right whales. These platforms have recorded acoustic signals produced by many other whale species, including the endangered Northwest Atlantic (NWA) blue whale, for which similar mitigation measures have not been established. This is because the source level of NWA blue whale vocalizations (e.g. Arch calls) and their detection range from gliders in the region remain unquantified. Yet, these parameters are necessary for cetacean density estimation and for evaluating the feasibility of using this call type for dynamic management frameworks. We take advantage of four ocean bottom seismometers (OBS) on which NWA blue whale calls were detected. We analyse a 1-hour subset of 79 Arch calls that were co-detected on glider and OBS data. The vocalizing whale is localized using a time-difference-of-arrival approach with a coupled ocean-acoustic model that incorporated spatially varying bathymetry, sound speed, and sediment properties. Received levels at each OBS were calibrated using a transfer function, derived from simultaneous particle-velocity and pressure measurements, to quantify the response of the seismometer to the waterborne acoustic wave. Source levels were then estimated using the calibrated received levels and a parabolic equation transmission loss model configured to the environment along the source-receiver path. Preliminary results from our case study demonstrate that Arch calls can be detected in the Northwest Gulf up to 125 km and 150 km from an OBS and glider, respectively, where the difference is primarily explained by the receiver’s position in the water column. The measured acoustic features of Arch calls suggest propagation similarities to infrasonic blue whale vocalizations (i.e., songs). These findings have ecological implications and can inform management strategies in an area heavily used by both whales and vessels.

How to cite: Goblot, E., Gehrmann, R., Barclay, D., Indeck, K., Plourde, A., Sirati, E., and Nedimović, M.: Seismoacoustic Localization and Source Level Estimation of Blue Whale Calls in the Gulf of St. Lawrence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11529, https://doi.org/10.5194/egusphere-egu26-11529, 2026.

The unstable rock slope "Spitze Stei" (Kandersteg, Switzerland) has shown significantly increased activity for several years. Since 2018, observed displacement rates can exceed 40 cm per day seasonally. The instability covers a total area of ​​approximately half a square km. The volume of the moving rock and debris mass is ~16 million m³, distributed across several rock compartments. Driven by degrading permafrost and enhanced gliding planes, these primary gravitational instabilities result in secondary, often destructive, debris flows into the Oeschibach channel. While continuous monitoring is essential for risk management, traditional visual and radar methods are often constrained by adverse weather conditions, limited temporal resolution and limited sensitivity to subsurface processes. To overcome these limitations and monitor rockslide internal deformation, material damage, and ongoing mass-movement processes at high spatial resolution, a dense temporary seismic network consisting of 64 SmartSolo nodes (natural frequency 5 Hz) were deployed across the slope at the end of June 2025 and operated for nearly three months. This dataset is complemented by recordings from three semi-permanent seismometers that have been operating since October 2021, providing a longer-term reference for background seismicity and site-specific noise characteristics.

We analyze the continuous seismic records to detect and characterize signals from a variety of mass-movement phenomena, including rockfalls, granular flows, debris flows and avalanche-related activity. Signals are evaluated based on waveform properties, duration, amplitude evolution, and spectral content, with comparisons across sensor types and periods. A key objective is to isolate and cluster internal microseismic activity, distinguishing it from background noise, external sources (e.g., icequakes), and transient permafrost-related signals.

Our preliminary results highlight a diverse set of seismic signal types linked to both surface processes and internal rockslide dynamics. This observed variability suggests changes in deformation style across different rock compartments, demonstrating the potential of dense nodal seismic arrays to resolve internal rockslide processes relevant for hazard monitoring.

How to cite: Das, B., Chmiel, M., Courboulex, F., Walter, F., Martin, X., Osorno-Bolívar, J.-S., Kienholz, C., Arias, G., and van den Ende, M.: Seismic Transients of Internal Deformation in an Active Rockslide (Spitze Stei, Switzerland): First Insights from a Dense Seismic Nodal Array , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12096, https://doi.org/10.5194/egusphere-egu26-12096, 2026.

Iceberg calving and near-shore landslides in Greenland produces seiches in the fjords - standing tsunami-like waves on the order of minutes of period that resonate for hours (or even days in extreme cases, see Svennevig et al., 2024), and can pose danger to the population and cause damage to infrastructure in the villages. For more than a decade, it has been known that broadband seismic sensors on-shore are sensitive to the ground tilt induced by these waves (Amundsen et al., 2012). Seiches are typically seen in seismic data as very long period waves that last tens of minutes to hours. This means that a network of on-shore seismic sensors can be employed to provide a tsunami early warning (TEW) system for both on-site and network-wide TEW. A major advantage of seismic networks over pressure gauges is the fact that the sensors are not exposed to the destructive forces of sea ice and icebergs, which are abundant in many regions of Greenland. In this work we demonstrate how a seismic network in the Uummannaq fjord (Greenland) can be used to provide TEW to the villages in the fjord. We further demonstrate an algorithm that allows detecting seiches and discriminating them from other sources of long-period signals (mostly large teleseismic earthquakes). Such an algorithm, however, can be significantly affected by corrupted data (spikes, steps, etc.), which produce false alarms. We then demonstrate how we can remove these false triggers using a deep scattering network (Seydoux et al., 2020). Our results show that we can detect seiches with little false alarms and provide timely TEW in the Uummannaq fjord, including the 2017 Nuugatsiaq landslide. We also demonstrate our implementation of the developed TEW algorithm into a real-time system in SeisComP. 

How to cite: Jozinović, D., Clinton, J., Massin, F., Seydoux, L., Mätzler, E., and Petersen, J.: Building a Demonstration Tsunami alert system in the Uummannaq fjord, Greenland, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12146, https://doi.org/10.5194/egusphere-egu26-12146, 2026.

Proglacial streams that drain Alpine glaciers are characterized by variable hydrological forcing and highly intermittent sediment transport, making continuous monitoring of hydro-sedimentary processes necessary to understand their dynamics. Near-field seismic monitoring has recently been established as a valid non-invasive approach to studying river dynamics, since ground vibrations are sensitive to both flow turbulence and bedload transport.

In this study, we analyse the seismic response of a proglacial stream fed by the Rutor Glacier, the sixth-largest glacier in the Italian Alps, integrating passive seismic monitoring with hydrological and climatic observations. Three geophones were installed close to the active channel and continuously recorded ground vibrations at 200 Hz during the 2025 ablation season (June–September). The seismic power spectral density was analysed across different frequency bands. Water level was monitored using pressure sensors, while discharge was estimated using saline dilution tests, allowing the relationship between seismic signals and hydrological forcing to be investigated.

The preliminary results show marked diurnal fluctuations in water level driven by glacial melt. At low frequencies (5–15 Hz), seismic power increases predominantly linearly with water level, suggesting a dominant control by water flow turbulence. In contrast, at relatively high frequencies (30–40 Hz), the seismic response becomes nonlinear and exhibits a clear change in slope when a critical water level is exceeded, suggesting the activation and/or intensification of bedload transport superimposed on the hydraulic signal.

This study highlights the potential of environmental seismology as a non-invasive and continuous monitoring approach to investigate hydro-sedimentary dynamics in highly variable proglacial environments.

How to cite: Marini, F., Piantini, M., Comiti, F., Bertagni, M., and Camporeale, C.: Frequency-dependent seismic response to hydrological and bedload forcing in a glacier-fed stream, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12535, https://doi.org/10.5194/egusphere-egu26-12535, 2026.

Understanding river sediment transport, and bedrock incision remains a major challenge in fluvial geomorphology Capturing their full temporal dynamics requires long-term monitoring of experimental catchments. This study explores the potential of Distributed Acoustic Sensing (DAS) technology to advance our understanding of fluvial sediment transport and riverbed evolution. DAS not only records strain or strain rates at meter-scale resolutions, similar to riverine dense geophone arrays but also captures a broad frequency range (mHz to kHz), comparable to hydrophones. Two experiments were conducted in meandering and straight artificial channels, with boundaries lined by waterproof membranes and stone protections, allowing for systematic effects of boundary and meandering shape. The experimental channels had a trapezoidal cross section, with widths ranging from approximately 2 to 4 m and bed slopes of 4–5°. During the experiments, the maximum flow depth reached about 0.3–0.4 m, the discharge ranged between 0.5 and 1 m³ s⁻¹, and the median grain size (D50) was approximately 10–20 mm. The experiments were monitored using a synchronized multi-sensor framework that combined UAV- and ground-based photogrammetry, particle tracking velocimetry, water-level gauges, stand-alone hydroacoustic sensor, riverine seismic dense array and DAS monitoring. Two fiber-optic burial configurations were examined for strain-rate sensing: (1) burial within a 30 cm thick sediment layer, and (2) installation beneath the armored riverbed (riprap) layer, allowing assessment of coupling conditions. Two-gauge lengths (2 m and 10 m) were also tested to evaluate their influence on strain-rate measurements. In our artificial channel experiments, the DAS measurements successfully captured high–spatiotemporal-resolution riverbed erosion and deposition dynamics. Fibers buried beneath the armored riverbed layer exhibited less sensitivity to riverbed morphological changes compared to those embedded within the sediment layer. In addition, the integration of DAS strain-rate, hydrophone, and riverbank seismic array data provided a comprehensive characterization of sediment transport processes across the channel. This study demonstrated that fluvial DAS enables continuous, high–spatiotemporal-resolution monitoring of sediment transport and riverbed evolution.

How to cite: Chao, W.-A., Hung, C.-Y., Chen, Y.-S., and Chen, S.-C.: Field-scale artificial channel experiments for fluvial DAS observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15481, https://doi.org/10.5194/egusphere-egu26-15481, 2026.

Farming practices reshape soil hydrodynamics by altering near-surface structure, mechanical stiffness, and water transport pathways, yet their impacts remain difficult to observe at field scale and high temporal resolution. Here we combine distributed acoustic sensing with physics-based hydromechanical modeling to quantify how tillage systems and soil compaction influences minute-scale, meter-scale seismic and hydrological responses in agricultural soils. We show that dynamic capillary effects govern transient soil stiffness and moisture redistribution following rainfall, with disturbed soils exhibiting sharp post-rain seismic velocity reductions associated with near-surface saturation. These responses are followed by pronounced hysteretic velocity recoveries driven by evapotranspiration, revealing strong memory effects in soil–water dynamics. Seismically inverted estimates of soil saturation demonstrate how farming-induced disturbance reshapes water flux partitioning and subsurface storage. Our results provide direct observational evidence that farming practices fundamentally reorganize soil hydrodynamics and establish distributed seismic sensing as a scalable, non-invasive approach for observing  soil processes relevant to land–atmosphere exchange, Earth system modeling, and resilience to hydrological extremes.

How to cite: Shi, Q., Denolle, M., Montgomery, D., Swann, A., Cristea, N., Williams, E., You, N., Collins, J., Prada Barrio, A., Jeffery, S., Misiewicz, P., and Nissen-Meyer, T.: How farming practices reshape soil hydrodynamics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16077, https://doi.org/10.5194/egusphere-egu26-16077, 2026.

Continuous seismic monitoring has proven effective for detecting rockfalls, yet most studies rely on multiple stations or dense arrays, increasing cost and complexity. This study demonstrates that a single seismic station, located approximately 100 m from the event site, can detect small rockfalls (<0.005 m³), characterize their dynamics, and estimate their volumes.

The approach relies on careful signal processing, combining STA/LTA analysis, envelope calculation, and parameters such as amplitude, duration, and frequency, to reveal distinctive features of rockfall events. This methodology emphasizes the quality of extracted information over the quantity of data, enabling real-time identification of minor precursory events even amidst diverse environmental and anthropogenic noise.

LiDAR and photogrammetry provide high-resolution spatial data to calibrate and validate detections, but their limited temporal resolution prevents continuous monitoring. Controlled block-fall experiments further optimized station placement and confirmed the system’s sensitivity. These results demonstrate the potential of cost-effective, single-station seismic monitoring for automatic rockfall detection and early warning, offering a practical solution for hazardous mountainous regions.

How to cite: Tapia, M., Guinau, M., Blanch, X., Abellan, A., Telletxea, B., Martín, J., and Meneses, F.: Seismic Monitoring of Rockfalls Enhanced by LiDAR and Photogrammetric Data: Towards Automatic Detection and Early Warning., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16328, https://doi.org/10.5194/egusphere-egu26-16328, 2026.

Information about frozen lakes, including ice rigidity, ice thickness, and water depth, is essential for environmental studies and practical applications. Although these properties can be measured in the field, such measurements are labor-intensive and spatially limited, motivating the development of alternative observation methods. Seismic waves provide an effective approach to studying frozen lakes, as their propagation velocity depends on the physical properties of the ice–water system, including the elastic moduli and thickness of the ice, and water column depth. In this study, we investigate the use of wind-driven flexural waves recorded by a distributed acoustic sensing (DAS) system to infer ice thickness and water depth beneath a 1000 m fiber-optic cable installed on Lake Pääjärvi, southern Finland. We identify wind-induced flexural waves in the 0.01-0.5 Hz frequency band, extract their dispersion curves, and invert them using a grid search to estimate effective ice thickness and water depth under four cable intervals. Our estimates indicate effective ice thicknesses ranging from 22 to 34 cm and effective water depths ranging from 0.8 to 31 m. Absolute differences between effective estimates and arithmetic averages of field measurements range from 0.5 to 8.6 cm for ice thickness and 1.2 to 10.3 m for water depth. Our estimates reproduce the observed dispersion curves and agree with field measurements, demonstrating that it is possible to obtain first-order information about ice thickness and water depth in frozen lake environments. However, the robustness of water depth estimates is limited by the wavenumber content of the flexural waves. In our case, the uncertainty of the water depth estimates increases from 0.43 to 12.05 m as water depth increases because low-wavenumber flexural waves, which are most sensitive to the water column, are not resolved by the dispersion curves. Another important observation is that refraction of flexural waves toward shallower water must be considered when converting apparent velocities measured along the cable to true velocities. If this effect is neglected, dispersion curves and the estimated parameters can be biased.

How to cite: Valero Cano, E., Moreau, L., Strobel, F., and Hillers, G.: Using flexural waves recorded by distributed acoustic sensing to infer the ice thickness and water depth of a frozen lake, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16347, https://doi.org/10.5194/egusphere-egu26-16347, 2026.

Soil is a complex ecosystem at the heart of survival for all life on land. Harbouring more carbon than the atmosphere and vegetation combined, it is home to more than 60% of Earth's species and delivers 99% of calories for the human food system. Despite growing demands, more than 70% of global arable land is classified as degraded. Monitoring soils and thereby improving soil health at scale is difficult due to their multiscale heterogeneity, limited accessibility of remote sensing techniques, and destructive, labour-intensive nature of soil coring, on the other hand. Geophysical techniques offer a tangible alternative. To date, active seismics have scarcely been considered for the living topsoil, a layer mere 10-50 cm below our feet.

We show how seismology with ultrahigh frequency wavefields above 500 Hz generated by hammer strikes and recorded by cheap, bespoke geophones should allow us to infer on a variety of crucial soil health parameters, such as bulk density, soil moisture, topsoil depth, soil carbon, and more, which collectively give rise to determining soil function and health. We present consistently high data quality up to 1500 Hz collected across three continents in more than 10 ecosystems and crop types, showcase a pathway for automated data processing and inference, introduce novel low-cost MEMS sensors, and highlight emerging AI engines.

Our non-profit organisation, Earth Rover Program, is tasked with implementing the vision towards a global soil health assessment of unprecedented resolution and coverage. This, in turn, can eventually equip farmers with spatially explicit, local knowledge of their soils’ state and suggest remedial measures based on this novel data, with the potential to reduce environmental pressures and agricultural costs while increasing long-term yields.

How to cite: Bagagli, M., Davidson, K., Tsekhmistrenko, M., Collins, J., Wangechi, M., Mosongo, P., Leng, K., Meng, J., Masson, Y., Jeffery, S., and Nissen-Meyer, T.: A seismic shift for soil health monitoring: scalable, non-invasive seismology at the decimetre scale., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17225, https://doi.org/10.5194/egusphere-egu26-17225, 2026.

Rock fracturing plays a key role in the formation of mountain landscapes and natural hazards. Freezing is one of the main triggers of erosion and fracturing in the Alps. However, questions remain about the impact of freezing on the resonance frequency of rock pillars and the quantification of mechanical stress generated by ice in natural cliffs. 

To better understand the effect of frost at the centimeter and meter scale, long-term recordings were made using repeatable ultrasonic signals to measure both sound velocity and waveform changes. These observations are combined with the measurement of the pillar's fundamental resonance frequency. The investigated Tête Noire rock pillar consists of micaschist and is instably hanging above the city of Trient in the western Swiss Alps. 

The results show that during freezing, the fundamental resonance frequency increases by 50 %, the P-wave velocity increases by 17 %, and for later arrivals (coda wave) velocity increases by 4 %. After the freezing period, a irreversible drop in P-wave and coda wave velocities is visible, but not in the fundamental resonance frequency which is coming back to its initial value. This decrease in velocity is accompanied by a decorrelation of the ultrasonic waveforms. Reproducing the observed P wave velocity changes on 0.5m thick layer on a finite element COMSOL simulations of the pillar, we determine that the changes in velocity in the rock do not explain the fundamental resonance frequency changes. We therefore propose that the increase in fundamental resonance frequency results from ice filling the rear crack, and we estimate an order of magnitude of about 1.7 m for the ice height, compared with the initial crack size of 10 m. 

To estimate the freezing stress, from the measured velocity changes, we determined the acousto-elastic constant of the Tête Noire micaschist on a representative laboratory sample using uniaxial compression experiments. Those results reveal that the generated freezing induced stress are in the subcritical regime with an order of magnitude of a few tens MPa and are, hence able to damage slightly the rock, irreversibly. The drop in correlation coefficient and in the waves velocity support this conclusion. 

This work was funded by the European Research Council (ERC) under grant No. 101142154 - Crack The Rock project

How to cite: Rousseau, R., Starke, J., Bottelin, P., Moreau, L., Baillet, L., and Larose, E.: Estimation of Frost-Induced Stress Using Time-Lapse Ultrasonic Testing and their Effect on the Dynamics of an Alpine Rock Pillar, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17386, https://doi.org/10.5194/egusphere-egu26-17386, 2026.

The planet’s surface is a restless orator: its fractures, failures and flows in response to climatic, tectonic and anthropogenic forcing inscribe narratives in seismic waveforms. Our limited success in decoding these narratives by classification and attribution of complex, incognito signals, threatens to leave Environmental Seismology data-rich but epistemologically impoverished. We propose that geomorphic signals can be formalized as language and tracked as evolving lineages. Hence, we develop a self-organizing, classification method with comprehension, resulting in an explainable, evolving phylogenetic tree. Unlike supervised classification methods that require exhaustive labels or clustering algorithms that conflate statistical similarity with physical kinship, our classification tool learns without labels, generalizes without forgetting physics, and explains without obfuscation.

We present a “glass-box” classifier, unsupervised in perception but supervised in its definition, that treats seismic data not as flat feature vectors but as structured, generative text, translating ground motion into a lexicon of geomorphic processes. Our system discovers its own alphabet, syntax, and semantics: autonomously constructing a taxonomic tree for seismic events while remaining interpretable. To do so, we break down the continuous seismic signal into discrete "phonemes." Multi-scale temporal descriptors, impulsive micro-textures (1.25 s), meso-scale envelope dynamics (5 s) and slow background trends (20 s), compose a multi-metric feature suite. These windows are fused into a tensor encoding nonlinear force interactions, then discretized through RVQ into context-aware symbols. Thus, we replace the geometric rigidity of static clustering with a dynamic evolutionary state space where signal classes behave as adapted species (rockfalls, landslides, debris flows, mine collapses, volcanic tremors, GLOFs, tectonic and glacial earthquakes, nuclear explosions, anthropogenic noise), governed by the Free Energy Principle. Similarity of process signals is tripartite: syntactic (grammar divergence), information-theoretic (surprisal), and algorithmic (NCD). This distinguishes events that look alike but have differing mechanisms: a debris flow and lahar may share "rumble" words, yet obey distinct physical grammars.

Modeled on Darwinian phylodynamics, the spectral species defined by their grammatical structure (causality), "metabolize" incoming data by minimizing thermodynamic surprise. The populations undergo sympatric speciation, hybridization, commensalism, and extinction, disentangling the "phylogenetic distance" (similarity) between superficially similar signals, and ultimately resulting in optimized classification. The algorithmic biomimicry of our approach outperforms static taxonomies that fail in non-stationary Earth systems without retraining.

Applied to a global, geologically heterogeneous inventory of >6000 curated records, preliminary results show phonemes reliability reaches 94–98% across stations and a >50% drop in articulation-structure complexity from noise to geomorphic events. The inferred phylogeny is physically meaningful, decoupling categories in distinct topological manifolds, allowing the classifier to reject false positives without supervision. Uncertainty is metabolized: high-aleatoric/low-epistemic signals (inherent noise) separate from low-aleatoric/high-epistemic anomalies (black swans: candidate new species). Free Energy scores, combine complexity and inaccuracy, outperform baselines in robustness to gaps, clipping, and dropout by over 20%.

The model is self-interpreting; rather than an opaque class label, it outputs a semantic sentence, exposing the decision path to a physically meaningful event classification, whilst also encapsulating information unique to specific events. Legible, self-improving classification turns detection into naming, and identity into process understanding.

How to cite: Ursica, S. and Hovius, N.: Seismic events classification using language syntax and biomimesis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17578, https://doi.org/10.5194/egusphere-egu26-17578, 2026.

On 10 August 2025, a large landslide (>64×10⁶ m³) collapsed more than 1,000 m onto South Sawyer Glacier and into Tracy Arm fjord in Southeast Alaska. The resulting tsunami ran up the opposing fjord wall to a height of 480 m, the second-highest tsunami ever recorded.

The landslide was preceded by more than 24 hours of repeated microseismicity (up to M~2), with event rates increasing until ~1 hour before failure, signalling a transition to continuous slip of the overall rock mass.

The landslide generated globally observed body and long-period seismic waves equivalent to an Mw 5.4 earthquake, making it one of the largest-magnitude landslides in decades. From regional and global seismic data, we infer a total mass of ~370 million metric tons, exceeding estimates from remote sensing and DEM analysis. This discrepancy suggests that water displacement during the initial tsunami contributed to the long-period global seismic signal.

Following the landslide signal, we observe monochromatic seismic waves worldwide with dominant periods of 50, 52, 66, and 86 s. The 66 s mode is strongest and persists for >36 hours at regional stations. Surface-wave radiation patterns, numerical tsunami modelling, and SWOT satellite water-height observations support the genesis of a fjord-transverse landslide-induced seiche (LIS) in the central fjord. However, seismic radiation is more complex than that of the 2023 Dickson Fjord, Greenland LIS event, likely reflecting differences in the landslide location and its direction, fjord geometry, and interaction of multiple seiche modes.

Despite heavy summer vessel traffic in Tracy Arm, there were no fatalities, making this a near miss. Seismic observations, combined with remote sensing, provide a critical pathway for forecasting and early warning of cascading landslide–tsunami events and for understanding ice–land–water interactions in polar environments.

How to cite: Hicks, S., Shugar, D., Berdahl, M., Caplan-Auerbach, J., Ekström, G., Fathian, A., Geertsema, M., Higman, B., Karasozen, E., Lynett, P., Monahan, T., Roe, G., Svennevig, K., Van Wyk de Vries, M., and West, M.: Seismic observations and modelling of the August 2025 Tracy Arm, Alaska landslide, megatsunami, precursory seismicity, and seiche, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17665, https://doi.org/10.5194/egusphere-egu26-17665, 2026.

The Greenland Ice Sheet (GrIS) is a major contributor to global sea-level rise. However, predicting its future contribution remains complicated due to large uncertainties in modeling seasonal velocity variations. One of the key challenges is to better constrain the role of isolated subglacial water cavities. Over the melting season, water pressure within these cavities fluctuates, causing the glacier base to be coupled or decoupled from the bedrock. This process modulates basal friction, thereby influencing the velocity of the glacier.
Yet, the mechanisms by which these cavities depressurize by connecting to efficient drainage systems remain poorly understood, particularly for rapid drainage events where viscous creep cannot play a role (Mejia et al., 2021).
To investigate this phenomenon and identify key hydrological parameters, a dense seismic array (Gimbert et al., 2021; Nanni et al., 2021) and a GNSS station was deployed over purported subglacial lakes at Isunguata Sermia, West Greenland. In early September, the GNSS station highlighted a sharp decrease in ice surface elevation, accompanied by intense seismicity at the ice-bed interface. We used unsupervised machine learning to explore recorded seismic signals and identified Low-Frequency Icequakes (LFI), which do not follow classical rupture scaling laws. Additionally, many of these events were followed by a tremor with very low frequencies (~2 Hz). These tremors migrated spatially over time, following a diffusion pattern correlated with the ice surface subsidence, suggesting water migration at the ice-bed interface and thus, a lake drainage. However, the estimated diffusion coefficient is two orders of magnitude higher than predicted by Darcy's flow law. This suggests a hydrofracturing mechanism, facilitating rapid connections between multiple isolated cavities rather than a simple, localized lake drainage process.
Unlike previous interpretations of LFIs observed on glaciers (Thelen et al., 2013; Helmstetter, 2022), our findings suggest that these events do not represent stick-slip mechanisms at the glacier base but are instead, generated by fluid pressure diffusion due to the pressure difference between two isolated cavities. To further support this idea, we propose a theoretical forward model for seismic noise generation driven by pressure diffusion. The model is based on the geometric and hydrological characteristics of the cavities, including cavity width, inter-cavity spacing, the diffusion coefficient and the water volume. Accurate identification of these parameters, based on observations allows us to reproduce the key features of the observed power spectrum.

How to cite: Rousseau, H., Le Bot, J., Gimbert, F., Esfahani, R., Campillo, M., Doyle, S. H., Livingstone, S., Sole, A., Michel, A., Paris, N., and Le Bris, T.: Low frequency icequakes as the signature of transient subglacial water flow underneath the Greenland Ice Sheet, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18176, https://doi.org/10.5194/egusphere-egu26-18176, 2026.

Environmental seismology increasingly employs relative changes in seismic velocity (dv/v) with time, derived from continuous seismometer recordings, to infer temporal variations in ground properties such as soil moisture and groundwater dynamics. However, despite that widespread use, there is no consensus on optimal frequency bands and stretching time windows used to extract reliable dv/v time series. Previous studies addressing deep, and shallow groundwater dynamics each applied distinct combinations of frequency bands and stretching time windows, raising the key question: how comparable are dv/v results derived from different parameter choices, and how consistently do they represent subsurface hydrological variability?

This work presents an intercomparison of commonly used noise-based dv/v combinations of frequency bands and stretching time windows across two hydrological domains: (1) groundwater at depth, and (2) shallow critical zone hydrology. For each domain, we review and implement published combinations of the previous parameters and assess their influence on the resulting dv/v time series.

To evaluate their methodological impact, we compare the different dv/v estimates amongst themselves and against independent environmental control datasets, including groundwater levels, soil moisture time series, and additional hydroclimatic observations. For both domains, we complement literature case studies with our own two field datasets from Germany, one in the Eifel and one in the Harz region. In the Eifel region, a network of ten seismic stations has been deployed across two sub-catchments in the upper Ahr Valley, composed of intensively folded and fractured Devonian mudstone and carbonate rocks. Continuous seismic records are paired soil moisture sensors at depths down to 40 cm and groundwater well measurements from nearby monitoring sites. In the Harz Mountains, we use additional seismic, top soil moisture, and hydrological observations to extend the comparison to a geologically and hydroclimatically distinct setting, with variable soil cover on weathered granite boulders creating abundant water flow in the shallow subsurface.

We hypothesize that different combinations of frequency bands and stretching time windows will produce systematically distinct dv/v patterns, even when applied to the same dataset, and that their sensitivity will vary across deep groundwater systems and shallow surface hydrology. By identifying parameter combinations that enhance or mask relations with the independently sensed environmental variables, this study aims to better understand methodological controls between these parameters and contribute towards a more consistent and comparable practice for environmental applications.

How to cite: Fracica Gonzalez, L. R., Andermann, C., Abadie, B., Armitage, J., Dietze, E., Hovius, N., Illien, L., Putzenlechner, B., and Dietze, M.: Evaluating Frequency Band and Stretching Time Window Effects on Noise-Based dv/v for Subsurface Hydrological Monitoring, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18499, https://doi.org/10.5194/egusphere-egu26-18499, 2026.

The composition, structure, and dynamics of a transient ice sheet that forms and disintegrates on a boreal lake is influenced by meteorological and environmental processes. This includes trapping of upwelling methane from the lake sediments, which is in turn affected by eutrophication in the catchment area. Methane is a potent greenhouse gas, yet documented sources and sinks to the atmospheric budget are highly unbalanced. Here we explore a novel approach for quantifying methane ebullition from a boreal lake that combines seismic methods together with interdisciplinary observation methods.

The DYNALake project centerpiece is an array of ~210 seismic geophones arranged in an aperiodic tiling configuration that we deployed in February 2025 on the ~20 cm thick ice of Lake Pääjärvi some 100 km north of Helsinki. The 10-km scale lake array is complemented by a sparser network of 31 land-based sensors installed around the lake between fall 2024 and spring 2025, three dense circular arrays enabling local beamforming and estimating array derived rotation, a DAS system with a 1 km-long fibre optic cable, an underwater echosounder to monitor potential methane ebullition, a rotational seismometer, a microphone to record seismo-acoustic waves, a Ground Penetrating Radar (GPR) survey, water chemistry measurements, manual ice thickness sampling and ice coring, and meteorological data. The project popularizes the subarctic wintertime fieldwork and the science by making a professional documentary for science communication, outreach, and education.

We present initial results on spatial and temporal variations in lake-ice thickness and on the quality and characteristics of the recorded seismic data. The observations include distinct ice-guided wavefield signatures, including QS₀ (quasi-symmetric) and SH₀ (horizontally polarized shear) modes used to estimate elastic parameters such as Young’s modulus and Poisson’s ratio, as well as the dispersive QS (quasi-Scholte) mode that is primarily sensitive to ice thickness at higher frequencies. We compare signals from natural sources and hammer shots across the different sensor types. We show examples of noise correlation wavefields, beamforming results, and seismo-acoustic records that can be used to characterize seismic activity patterns and resolve variable ice properties. Seismic activity in the 0.03–0.2 Hz band increases during high-wind episodes, while higher-frequency signals (0.1–1000 Hz) correlate with rapid air-temperature cooling events. The GPR profile images the spatial ice variability across the lake that is compatible with the in situ measurements. The geochemical water sample analysis suggests Lake Pääjärvi is a source of methane.

We discuss the potential of the data quality and the sensor configuration for signal detection and for icequake and passive tomography lake ice images to resolve spatially variable air and gas bubble properties that are controlled by environmental processes. This synthesis demonstrates that the application of environmental seismology concepts can form a bridge between bottom-up ebullition monitoring and remote-sensing approaches.

How to cite: Strobel, F., Hillers, G., Jilbert, T., Loehr, J., Stranne, C., Oksanen, T., Vänskä, J., Courbis, R., Rintamäki, A., Sadeghi-Bagherabadi, A., Weißgräber, L., Ding, Y., de Langenhagen, M., Valero Cano, E., Mordret, A., Schmelzbach, C., Moreau, L., Coutant, O., and Hadziioannou, C. and the DYNALake deployment team: Resolving environmental processes by imaging and monitoring lake ice properties of the boreal Lake Pääjärvi, southern Finland, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18667, https://doi.org/10.5194/egusphere-egu26-18667, 2026.

Slope instabilities pose an increasing threat to populations and infrastructure across various regions worldwide. Therefore, a fundamental understanding of processes governing slope failure is critical for improving hazard mitigation. While remote-sensing and synthetic aperture radar methods effectively capture surface displacement, they provide limited information on subsurface dynamics. Seismic monitoring and imaging techniques can provide valuable complementary information on the internal structure, material properties, and time-dependent processes associated with unstable slopes.

We present a large-scale application of long-term Distributed Acoustic Sensing (DAS) measurements to investigate the spatial and temporal evolution of microseismicity at Cuolm da Vi (Central Switzerland), one of the largest active slope instabilities in the Alps. We deployed a 6.5 km long fibre-optic array to record continuous DAS data over a five-month period in spring 2023. Using a coherence-based detection method that exploits the dense spatial sampling of DAS, we identified 1,277 local seismic events. Event locations were obtained by adapting a matched field processing (MFP) approach to DAS observations, resulting in a comprehensive microseismic catalogue. The localisation workflow was validated through a controlled-source experiment and by comparison with a traveltime inversion of manually picked arrivals for selected events.

The resulting event distribution shows a pronounced spatial correspondence with known tectonic structures at Cuolm da Vi, particularly steeply dipping fracture systems, suggesting that much of the observed seismicity is linked to internal deformation processes related to a toppling movement. Clusters of elevated event density coincide with regions of reduced seismic velocities or strong velocity contrasts inferred from an independently derived three-dimensional velocity model. During the five-month observation time, the seismicity exhibits three distinct phases of elevated activity, with the first two closely following periods of intense precipitation and snowmelt. In addition, distinct spatial migration patterns of seismic activity emerge across different timescales.

The findings of our study demonstrate that DAS enables long-term monitoring of microseismic activity over spatially extensive and challenging Alpine terrain. The results provide new constraints on the internal structure and evolving dynamics of the Cuolm da Vi instability and additionally, highlight the potential of DAS-based seismic monitoring to improve hazard assessment and advance our understanding of deep-seated slope failure processes.

How to cite: Kiers, T., Schmelzbach, C., Grimm, J., Amann, F., Maurer, H., Edme, P., Bonanomi, Y., and Robertsson, J.: Fibre-Optic Monitoring of An Alpine Slope Instability Using Seismic Events: A Spatio-Temporal Analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18693, https://doi.org/10.5194/egusphere-egu26-18693, 2026.

Landslides remain one of the most pervasive natural hazards in the Himalayan region, exacerbated by intense rainfall, steep topography, and anthropogenic activity. Accurate detection, monitoring, and hazard zoning of these slope failures are essential for mitigating their impact on communities and infrastructure. This research integrates Synthetic Aperture Radar Interferometry (InSAR) with Seismic Ambient Noise Interferometry (SANI) monitoring to provide a comprehensive assessment of landslide-prone regions. Using time-series InSAR techniques such as Persistent Scatterer (PS-InSAR) and Small Baseline Subset (SBAS) interferometry, implemented through open-source tools like OpenSAR Lab, MintPy, LiCSBAS, and StaMPS, we processed multi-temporal SAR datasets from January 2020 to December 2024 to retrieve surface deformation rates. This analysis enabled the identification of both active and slowly deforming landslides across the study area. 

The seismic velocity change was computed to monitor subsurface behavior from 17th June 2024 to 17th July 2024 using three seismic stations, viz AULI, CHAD, and KVSJ, located in Joshimath, Chamoli. The dv/v calculate for KVSJ shows a prominent velocity drop on July 5th, 2024. The landslides occurred on the 9th and 10th of July 2024. The drop in velocity can be attributed to increased moisture due to precipitation, which results in rigidity loss. The observed velocity drop may be interpreted as a precursor signal to landslide occurrence. However, the dv/v plots for the AULI and CHAD do not show any prominent drop in the velocity. The one possible reason could be the aspect of the downslope area that orients to a relatively stable valley bottom. As the region hosts metasedimentary rock, the subsurface response to the infiltration of rainwater could also have contributed to the different behavior of these two stations, and this is to be further investigated to identify the plausible causes.

The integrated methodology presented in this work demonstrates that the synergy between InSAR and passive seismology not only improves landslide detection and monitoring capabilities but also contributes to more informed early warning systems and risk reduction strategies. This study contributes to the broader goal of disaster-resilient infrastructure planning in mountainous terrains.

How to cite: Mishra, S. and Maurya, S.: Landslide Monitoring in Joshimath through Passive Seismology and SAR Interferometry, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21031, https://doi.org/10.5194/egusphere-egu26-21031, 2026.

During the melt season, subglacial drainage systems typically evolve from a high-pressure, distributed system to a low-pressure, channelized network that progressively extends up-glacier from the terminus in response to meltwater availability. Resolving the spatial and temporal evolution of this transition remains challenging, particularly with small seismological networks, or even single stations.In spring 2023, we deployed three seismological stations along the central flow line of the southeast outlet glacier of the A. P. Olsen Ice Cap, northeast Greenland. The stations spanned the full vertical extent of the ablation zone and continuously recorded throughout the 2023 melt season.We apply and compare different seismological analysis techniques with the potential to detect changes in subglacial hydrological conditions. The seismic observations are interpreted in conjunction with meteorological data from two automatic weather stations located in the lower and upper ablation zone. We assess the capability of environmental seismological monitoring with single stations to track drainage system development in space and time.

How to cite: Binder, D., Mertl, S., Larsen, S. H., and Eibl, E. P. S.: Can we track the up-glacier migration of a subglacial channelized drainage system by means of environmental seismology?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21131, https://doi.org/10.5194/egusphere-egu26-21131, 2026.

Large earthquakes can trigger cascading environmental impacts in continent (e.g. 1964 Mw 9.2 Alaska and 2015 Mw 7.9 Nepal earthquakes), yet such processes remain poorly documented in oceanic and polar settings. Here, we present a multidisciplinary investigation of the 2025 Mw 6.5 oceanic strike-slip earthquake that occurred on 10 March 2025 along the Jan Mayen oceanic transform fault, Arctic Ocean, and its surface and cryospheric impacts on local Jan Mayen Island. Using relocated local seismicity, regional waveform modelling, GNSS time series, seismic noise interferometry, infrasound observations, high-resolution optical satellite imagery, and long-term air-temperature records, we reconstruct the sequence of events linking the earthquake rupture to a major rock-slope failure. The earthquake, which ruptured for ~40 km long in transform faulting, triggered a rock avalanche from a steep, glacier-adjacent volcanic slope, depositing 0.8-1.2x10⁶ m³ of debris material over ~0.9 km² of the Kjerulf Glacier and reaching the coastline. Infrasound signals constrain the timing of slope failure to within minutes of the mainshock, supporting a co-seismic trigger. Satellite imagery further reveals contemporaneous calving at the Weyprecht Glacier. We observed from pre-2025 satellite imagery that multiple smaller rock-slope failures between 2019 and 2024, indicating progressive slope weakening prior to the earthquake. Also, long-term air-temperature records show a marked warming trend over recent decades, including the near absence of extreme cold winters since the late 1990s and an increasing frequency of anomalously warm summer days, consistent with Arctic amplification. We interpret the 2025 rock failure at Kjerulf Glacier as an earthquake-triggered collapse of a slope preconditioned by permafrost degradation associated with this warming trend. Our results demonstrate that oceanic strike-slip earthquakes can generate significant onshore geohazards in polar environments and highlight the importance of integrated geophysical and remote-sensing approaches for monitoring earthquake-climate-cryosphere interactions in the Arctic.

How to cite: de Melo, G. W. S., Hermanns, R., Bendle, J. M., Grevemeyer, I., Cesca, S., do Nascimento, A. F., Ottemöller, L., Aslan, G., Brissaud, Q., Oye, V., and Kopp, H.: An earthquake-triggered rock avalanche on Jan Mayen Island conditioned by Arctic warming, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22884, https://doi.org/10.5194/egusphere-egu26-22884, 2026.

As a part of the bilateral project between France and Serbia “Erosion Unveiled: AI-Driven Insights into Lithology and Climate Change Impacts” EARTH both the French and Serbian teams have started to develop interdisciplinary collaboration at the interface between artificial intelligence and geosciences. The joint activities have focused on the development of predictive and causal models for weathering changes of sediment of different lithology, combining in-person research exchanges, data-driven experimentation, and methodological design.

Ideal landscapes for this type of study are badlands, characterized by limited vegetation, minimal human activity, and a variety of active geomorphological processes such as weathering, erosion, landslides, and piping. These areas can develop under a wide range of climatic conditions, and their formation is controlled by the interplay between lithology, terrain morphology, climate, and erosional processes. Previous research has shown that different lithologies display distinct erosion rates and geomorphic behaviors, while even areas composed of the same lithology may respond differently depending on environmental conditions. Such variability has become increasingly relevant in the context of global climate change.

The main aim of this joint research is to connect the sediment properties to the behavior of the rocks from the weathering experiments and to summarize the data to improve the prediction model. Therefore, in this study a database compiled of results from 10 weathering experiments of badland materials using simulations of different types of precipitation (rain and snow) and drying conditions (from -4 °C to 40 °C). The dataset includes the following leachate properties: volume, pH, EC, and ion concentrations.

After performing the necessary data processing methods (handling of missing data, normalisation, etc.), we make use of standard supervised machine learning (including random forest, temporal convolution networks, recurrent neural networks) and multimodal data fusion techniques combining laboratory-derived measurements with image-based features of sediment samples to perform various predictions. To identify key material properties that influence the development of badlands terrain, we explored and discussed the result of different XAI approaches. Those include gradient-based explanations, perturbation-based methods (LIME and SHAP),  and the creation of surrogate models. Based on these results, a data-driven classification of erodible sediments is proposed, as well as predictive models that allow for accurate forecasting of terrain evolution under different climatic conditions.

By integrating AI with detailed laboratory-derived data, our research provides a complementary perspective on badland material evolution. This approach not only enhances model interpretability but also opens new possibilities for hybrid geomorphic modeling, where material characteristics are used to develop more robust and transferable predictions. Ultimately, this study highlights the potential of AI-driven methods to improve our understanding of erosion processes and contribute to the development of more transparent, reproducible, and data-rich frameworks within geomorphological research.

How to cite: Stefanović, M., Kašanin-Grubin, M., Antić, N., Brouat, M., Yun, B., and Vesic, S.: Linking Sediment Properties and Erosion Dynamics in Badlands Using Machine Learning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-459, https://doi.org/10.5194/egusphere-egu26-459, 2026.

Recent advances in Artificial Intelligence (AI) and computer vision have opened new opportunities for automated monitoring and analysis in geomorphology. Among these, optical flow methods represent a powerful approach for quantifying surface velocity fields in rivers using video data. This work presents the development and application of a low-cost optical flow tool designed to estimate river surface velocity from fixed monitoring points, offering a practical and scalable solution for hydrological and flood-risk management applications.

The proposed method relies on the implementation of an AI-assisted optical flow algorithm capable of tracking the motion of water surface patterns (e.g., ripples, foam, floating debris) in standard RGB video sequences. By leveraging dense flow estimation and adaptive filtering, the tool produces high-resolution velocity maps that can be continuously updated in near real time. The system has been tested in different riverine environments, showing robust performance under varying lighting and flow conditions, and demonstrating its ability to capture both steady and transient flow dynamics.

One of the key strengths of this approach lies in its low operational cost and flexibility. The method can be implemented using conventional cameras and open-source software, eliminating the need for expensive. This makes it particularly suitable for establishing permanent observation points in critical areas, such as flood-prone zones or regions with limited monitoring infrastructure. Continuous optical monitoring of surface velocity provides valuable information for calibrating hydrodynamic models, identifying changes in river morphology, and supporting early-warning systems for extreme hydrological events.

Beyond the technical development, this research emphasizes the importance of integrating AI-based monitoring tools within broader frameworks for territorial management and risk mitigation. Establishing collaborations with stakeholders such as Basin Authorities, local governments, and civil protection agencies—can significantly enhance the effectiveness of these systems. Shared data platforms and automated AI-driven analytics could enable more proactive responses to extreme events, improving preparedness and resilience in flood-prone communities.

In future developments, the integration of deep learning models for feature detection and noise reduction could further enhance the accuracy and robustness of surface velocity estimation. Combining optical flow data with other remote sensing sources (e.g., UAV imagery, satellite observations) could also provide a multi-scale understanding of fluvial dynamics. This research thus contributes to the growing field of AI applications in geomorphology, highlighting how intelligent, low-cost monitoring systems can play a crucial role in sustainable river management and flood risk assessment.

How to cite: Sabato, G., Luparelli, A., Chirivì, M., and Lupi, A.: Optical Flow-based Tool for Surface Velocity Monitoring in River Systems: A Step Toward AI-driven Flood Risk Management, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1142, https://doi.org/10.5194/egusphere-egu26-1142, 2026.

The Mediterranean Sea is often affected by tropical-like cyclones, which cause heavy rainfall, strong winds, storm surges and flooding. The accurate classification of precipitation into convective and stratiform within these systems is essential for understanding storm dynamics and improving predictive models. In this study, we developed a deep learning approach based on U-Net architecture to classify convective and stratiform precipitations during Mediterranean cyclones using the Global Precipitation Measurement (GPM) IMERG product. We derived physically consistent labels for training through an exponential distribution-based thresholding of rainfall intensities. The trained U-Net model effectively reproduced the spatial structure of convective rainbands and surrounding stratiform regions within the cyclone structure. In addition to validating the convective precipitation detection using brightness temperature satellite observations and ERA5 reanalysis, we also incorporated pluviometer records. These ground-based measurements confirmed the model’s strong capability to identify areas affected by convective precipitation. This study demonstrates the potential of integrating a physics-based approach with deep learning for high-resolution characterization of precipitation in Mediterranean cyclones. While the segmentation of convective precipitation alone does not directly quantify coastal hazard, these results provide essential input layers for downstream coastal-impact assessments. In particular, the high-resolution identification of convective rainfall can be integrated into hydrological and hydraulic models (e.g., HEC-RAS or similar) to simulate surface runoff, flash-flood dynamics, and related coastal impacts under a changing climate.

How to cite: Kushabaha, A., Alemán, J. J. G., Miglietta, M. M., Mastrangelo, D., and Panegrossi, G.: Evaluation of a deep learning model to classify convective and stratiform precipitation patterns , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1804, https://doi.org/10.5194/egusphere-egu26-1804, 2026.

Human activities are increasingly degrading European coastal seabed, highlighting the need for efficient monitoring tools. To address these impacts, the Marine Strategy Framework Directive (MSFD) was established in 2008 with the aim of protecting and preserving marine ecosystem while ensuring their sustainable use.

Within this framework, high-resolution seafloor mapping represents a fundamental tool for coastal governance, habitat monitoring and marine geological studies. Fine-scale survey using Side-Scan Sonar (SSS), often integrated with AUV systems, provides detailed information on seabed morphology and acoustic facies, supporting habitat mapping and coastal management.

Recent advances in artificial intelligence (AI) and machine learning (ML), combined with Geographic Information Systems (GIS), have significantly improved the automated interpretation and mapping of submerged morphological features from marine geophysical data. In this context, this study investigates the application of computer vision techniques to nearshore environments along the Italian coastline, with a specific focus on the Segment Anything Model (SAM) framework.

We evaluate both the foundation-model implementation of SAM (SAM2) and its prompt-driven variant (SAM3) for the detection and classification of seafloor features in high-resolution SSS mosaics. The analysis was conducted on three nearshore areas in the Apulia region (southern Italy): Torre Guaceto (BR), Leporano (TA) and Zapponeta (FG). Using SAM2, we implemented a supervised workflow in which manually segmented features, including ripple marks, coralligenous formations, seagrass beds, sandy plains and rocky outcrops were used to train a Contrastive Captioner (CoCa) classifier via transfer learning. This approach achieved a test Macro F1 score of approximately 0.90.

In parallel, the text-promptable SAM3 model was employed for zero-shot segmentation of small, high-backscatter point-like features (“white dots”). These features were validated through an independent AUV-based video survey and confirmed to correspond to coralligenous formations. This result demonstrates the capability of SAM3 to rapidly extract geologically meaningful targets without requiring prior training.

Future developments will focus on alternative strategies and model refinement to further improve detection accuracy and robustness.

How to cite: Parisi, F., Scarrica, V. M., De Giosa, F., and Staiano, A.: Automated seafloor feature recognition in Side-Scan Sonar data using Segment Anything Models (SAM): a case study from Apulian coastal nearshores, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3878, https://doi.org/10.5194/egusphere-egu26-3878, 2026.

Alluvial-coastal plains and shallow-marine areas are facing increasing hydrological pressure from rising sea levels, changing precipitation patterns, and more frequent extreme events that alter their water balance. Prolonged droughts and unsustainable freshwater withdrawals further exacerbate the problem, causing saline intrusion into already vulnerable aquifers. In this context, adjusting drainage channel levels has become a key climate adaptation strategy. Our work combines long-term forecasting of aquifer dynamics using hydro-climatic data, including meteorological forecasts, with near-real-time forecasting to optimize the operation of high-capacity pumping stations that safeguard the drainage network of San Rossore Migliarino Massaciuccoli Regional Park (Pisa, Italy). The study addresses two complementary forecasting approaches: 1. Extended-range forecasting of aquifer levels through the integration of historical groundwater measurements and meteorological forecasts, with particular emphasis on precipitation and temperature projections over a two-week period. This approach provides weekly predictive outputs essential for determining optimal operational thresholds for pump activation, accurately tailored to varying seasonal and meteorological conditions throughout the year. 2. An operational, near-real-time forecasting framework designed to support daily management decisions. This system incorporates real-time data on meteorological conditions, groundwater levels, channel hydrometric levels, and drainage system activity to serve as an early warning mechanism during exceptional events requiring prompt intervention. Overall, preliminary results unequivocally highlight how integrated long-term and near-real-time operational forecasting systems are now indispensable for sustainable and resilient water resource management. Such systems allow for proactive anticipation of critical conditions, optimized drainage system use, reduced energy consumption, and preservation of the hydro-saline equilibrium in coastal aquifers. This emphasizes the necessity for continuous monitoring and technologically advanced solutions in fragile alluvial-coastal plains facing intensifying climatic and anthropogenic pressures.

How to cite: Lupi, A.: Integrated forecasting approaches for optimizing alluvial-coastal drainage systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4986, https://doi.org/10.5194/egusphere-egu26-4986, 2026.

Badland landscapes, characterised by intensely dissected slopes on unconsolidated sediments or soft rocks, are crucial hotspots for understanding soil erosion and sediment transport dynamics. Consequently, alongside their rapid climatic responses and links to anthropic land use, the geomorphological processes driving badlands morphogenesis are widely studied; recently, approaches combining multiplatform remote sensing and Machine Learning (ML) have been proposed due to their superior performance compared to other statistical models.

This study develops an integrated and multi-source approach using detailed geomorphic and hydrological parameters through a Random Forest (RF) algorithm to obtain a high-resolution land cover classification and erosion susceptibility maps of badland landscape in Basilicata Region (Italy). The workflow analyses geomorphological data at the micro-topography scale (3 cm/px) for geomorphometric landscape classification. Topographic and hydrological predictors were extracted from high-resolution Digital Elevation Models (DEMs) and orthomosaics were derived from optical images acquired in a drone survey conducted in May 2025. Spanning 0.025 km², the study area exhibits characteristic badland morphologies, located on poorly cemented silty clays from the Lower Pleistocene. Two different experiments were conducted. In the first one, ten topographic and hydrological predictors (e.g. Topographic Position Index, aspect, profile and tangent curvatures, Stream Power Index) were computed using open-source GDAL and GRASS GIS tools to assemble a multi-layer spatial dataset. In the second experiment, the R, G and B bands from the optical orthomosaics were also considered and included as three additional predictors. In both the experiments, 9,900 training points and 3,000 test points were extracted from the dataset to conduct a spatial cross-validation. Following the accuracy assessment, the algorithm was retrained on the full dataset to generate: i) a land cover map of three features: ‘Badland’, ‘Vegetation’ and ‘Pediment’; and ii) an erosion susceptibility map based on the probability of a pixel belonging to the ‘Badland’ class. The first experiment using only morphometric predictors showed a global accuracy of 82.49%, while the second experiment integrating the three RGB bands increased accuracy to 97.43%.

How to cite: Sozio, A., Marsico, A., Colacicco, R., La Salandra, M., Muscillo, S., Refice, A., and Capolongo, D.: Machine Learning techniques for the detection of geomorphological features in badland landscapes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7293, https://doi.org/10.5194/egusphere-egu26-7293, 2026.

In formerly glaciated regions, high resolution multibeam bathymetry is crucial to understand submarine glacial landforms and the processes that formed them. Using submarine glacial landforms to study past glacial dynamics contributes to the understanding of how glacial margins will change in the future. The increase in mapped seafloor coverage also creates an opportunity to develop and deploy automated models for recognizing and classifying glacial and glacimarine features. Datasets of glacial and glacimarine features were developed from manual interpretation of multibeam bathymetry from the deglaciated shelves of Svalbard and Antarctica. Features were assigned to one of 10 classes: crag and tails; flutes and drumlins; grounding zone wedges; mega-scale glacial lineations; channels; iceberg ploughmarks; large moraines; small moraine ridges; planes; and bedrock structures. Additional morphological analysis was performed for each feature in both datasets. For each sample, inputs to the model included bathymetry, slope, aspect, profile curvature, tangential curvature, and the rasterized outline of the feature of interest. We performed classification using six established Convolutional Neural Network (CNN) architectures, including ConvNeXtTiny, DenseNet201, EfficientNet, MobileNet, ResNet50, a baseline Simple CNN in addition to a Genetic Conditioned Convolutional Neural Network (GC-CNN). Three approaches were taken using the datasets: 1) Training separate models using the Svalbard and Antarctica datasets with testing only on the same dataset. 2) Training separate models using the Svalbard and Antarctica datasets and testing on the other dataset. 3) Training a combined model using all available data from both datasets and testing on a separate dataset from North Greenland. Our results show that morphological differences between features from different regions have a significant effect on machine learning model accuracy. Developing robust glacial landform classification models that can be applied to features from all regions require data that capture the variability of a particular feature class.

How to cite: Danielson, M., Truong, T., and Jakobsson, M.: Comparison of Machine Learning Results of Glacial Landform Classification of Datasets From Svalbard and Antarctica, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10389, https://doi.org/10.5194/egusphere-egu26-10389, 2026.

Obtaining information on the size and shape of individual sediment grains is fundamental to many geoscientific applications, as these properties provide insights into sediment transport and depositional processes. Conventional approaches for grain size and shape analysis rely on manual or semi-automated workflows and are therefore labor-intensive and time-consuming. Recent advances in deep learning, particularly in image segmentation and object detection, have enabled the development of automated methods for measuring grain size and shape. However, existing approaches typically are trained on homogeneous, task-specific datasets, which limits their ability to generalize across different data types and settings. Additionally, challenging image characteristics often compromise the segmentation accuracy.

We present an upgraded version 2.0 of the ImageGrains framework (Mair et al., 2024), which leverages a recently published next-generation segmentation model, Cellpose-SAM (Pachitariu et al., 2025). We re-trained this model on our newly released open-access dataset comprising 243 images and more than 29,000 manually annotated sediment grains. This dataset consists of images from various settings, including photographs of fluvial gravel, coarse pro-glacial deposits, and X-ray computed tomography scans of glacial till and marine sand. We use these data to benchmark the segmentation performance of the method against ground-truth annotations and to compare it to the performance of existing segmentation methods.

The results show that ImageGrains 2.0 achieves higher segmentation accuracy and improved generalization to previously unseen data compared to current state-of-the-art methods. When comparing the size and shape of grains predicted by the model with the ground truth annotations, we find that the increase in segmentation accuracy of our upgraded framework directly translates to more precise and realistic morphometric results, such as grain size distributions. We make our framework available to the community as a free and open-source installable Python package, as well as through interactive computing environments such as Jupyter Notebooks and a graphical user interface.

References

Mair et al. (2024): Automated detecting, segmenting and measuring of grains in images of fluvial sediments: The potential for large and precise data from specialist deep learning models and transfer learning, ESPL, 49, 1099–1116, https://doi.org/10.1002/esp.5755.

Pachitariu, et al. (2025): superhuman generalization for cellular segmentation, https://doi.org/10.1101/2025.04.28.651001.

How to cite: Mair, D., Witz, G., Do Prado, A., Garefalakis, P., Wild, A., Ville, F., Schuster, B., Horn, M., Österle, J., Fabbri, S., Litty, C., Achleitner, S., Leistner, S., Hiller, C., and Schlunegger, F.: Introducing ImageGrains 2.0 for improved grain size and shape measurements in 2D and 3D data from images of sediment, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10505, https://doi.org/10.5194/egusphere-egu26-10505, 2026.

Recent advances in deep learning, particularly convolutional neural networks (CNNs), together with the increasing availability of high-resolution multibeam bathymetry data, have made automated classification of glacial landforms increasingly feasible. However, robust and scalable classification remains challenging. The main challenge is not only computational scale, but the mismatch between data-driven learning and the physics-governed nature of glacial terrain. To address this gap, we propose a physics-informed deep learning framework for automated classification of submarine glacial landforms from multibeam bathymetry. Unlike conventional CNNs that rely purely on data-driven features, our approach integrates physically meaningful constraints reflecting glacial geomorphology. Specifically, we develop a Physics-Informed Genetic-Conditioned Network (PI-GCNet) by integrating a genetic-conditioned layer into a standard CNN and introducing a physics-guided loss that enforces geomorphological consistency. Each landform class is represented by a learnable genome vector initialized from class-wise statistics of depth, slope, and curvature and trained jointly with the embeddings. A genetic attraction and repulsion mechanism structures the latent space, and classification is performed via an energy-based distance between embeddings and genomes. We further optimize a composite objective combining genetic Cross-Entropy, genome regularization for stable and interpretable representations, and a class-wise slope deviation loss penalizing departures of predicted mean slope from expected class-specific values. Together, these components enhance robustness and interpretability, enabling scalable and physically consistent mapping of submarine glacial landforms. We validate the proposed model using high-resolution multibeam bathymetry acquired in northern Greenland. We prepared a dataset of 1515 samples across 10 classes of glacial and glacimarine features identified through manual interpretation. Model inputs include bathymetry, slope, aspect, profile curvature, tangential curvature, and the rasterized outline of each feature. In addition, we compare PI-GCNet with state-of-the-art deep learning baselines to demonstrate reliability and improved generalization.

How to cite: Truong, T., Danielson, M., and Jakobsson, M.: Physics-Informed Genetic-Conditioned Network for Glacial Landform Classification, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10851, https://doi.org/10.5194/egusphere-egu26-10851, 2026.

Drumlins are key indicators of subglacial processes and former ice-flow patterns, but regional drumlin inventories are often compiled manually, limiting scalability and reproducibility. This contribution presents a workflow for drumlin segmentation, prediction, and GIS-ready analysis using deep learning applied to digital elevation models (DEM) and an existing, manually mapped, drumlin reference shapefile from Latvian drumlin fields. The DEM is tiled into 640×640 image patches, and reference polygons are converted into You Only Look Once (YOLO)(Ultralitics S.a.) segmentation labels. A YOLOv11 segmentation model is trained for drumlin delineation and then used to generate predictions across the tiled DEM. Predicted outputs (TXT masks) are converted back into georeferenced polygons and exported as GeoPackages, enabling immediate integration with standard GIS-based morphometric analysis and mapping methods.

Model performance is evaluated using both standard YOLO metrics and an inventory comparison against the control dataset. The statistics for bounding boxes, precision and recall reach 0.808 and 0.652, with mAP50 of 0.755 (mAP50–95: 0.514). For segmentation masks, precision and recall are 0.757 and 0.601, with mAP50 of 0.672 (mAP50–95: 0.275). Inventory comparison yields 1190 predicted vs 1146 control drumlins, with 906 true positives, 284 false positives, and 247 false negatives, corresponding to precision 0.761, recall 0.786, and F1 0.773 (nMCC: 0.387).

The results demonstrate that YOLO-based segmentation can produce georeferenced drumlin polygons at scale with quantified uncertainty, providing a practical route toward repeatable drumlin inventories and downstream geomorphological analyses.

This research was funded by the Latvian Council of Science, project "Reconstruction of ice stream dynamics and deglaciation of the SE sector of the Scandinavian Ice Sheet in Latvia", project No.lzp-2024/1-0193

How to cite: Puriņš, H. H.: ML assisted drumlin inventory: YOLOv11 segmentation, polygon reconstruction, and accuracy assessment, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11575, https://doi.org/10.5194/egusphere-egu26-11575, 2026.

Effective monitoring of hydro-geomorphological processes such as sediment displacement and channel migration using UAV-captured RGB images requires accurate, temporally consistent 3D reconstructions that enable the estimation of height/volume changes across multiple acquisitions epochs, despite variations in imaging conditions, flight paths, and camera geometries. Neural Radiance Fields (NeRF) offer a powerful framework for reconstructing complex fluvial environments from multi-view imagery. However, standard NeRF training relies on equal‑probability random pixel sampling, a strategy that introduces stochasticity into the reconstruction process and undermines the temporal repeatability required for change detection. When separate NeRFs are trained for different epochs the random sampling of pixels – combined with differing camera poses – leads to inconsistent ray distributions and surface sampling, and reduced comparability of resulting reconstructions. These effects are particularly detrimental in dynamic river corridors where low-texture surfaces, water reflections and surface motions already limit reconstruction coverage and stability.

We propose Coverage-Efficient Non-redundant Sampling (CENS) as a grid-based deterministic alternative to random pixel sampling in NeRF training, combined with a pose-consistent inference framework, to improve temporal reconstruction repeatability for hydro-geomorphic change analysis. Instead of randomly sampling pixels per iteration, we impose a spatially deterministic sampling grid that ensures intra-epoch spatial coverage and consistency. To address the challenge of differing camera poses between epochs, we introduce a cross‑epoch evaluation strategy in which all epochs are queried using a shared set of reference camera poses – either drawn from one epoch’s camera set or defined as a synthetic virtual camera lattice – after alignment to a common world coordinate frame. This enables pose‑consistent rendering across time even when the original acquisition geometries differ.

Rendered depth maps from these shared viewpoints are then projected onto a fixed world-space grid, enabling cell-wise comparison of height and volume change. This two-layer determinism—fixed sampling during training and fixed camera/grid sampling during inference—decouples temporal analysis from the stochastic and pose‑dependent variability inherent in standard NeRF pipelines.

We will evaluate the method on multi‑epoch UAV imagery of an active river reach, comparing reconstructions trained with traditional random pixel sampling against those produced using the proposed CENS approach. With improved intra-epoch spatial coverage and geometric stability, combined with pose-consistent inference, we anticipate that the proposed approach will yield more coherent inter-epoch estimates of sediment elevation, channel-bed change and/or bank erosion, with lower uncertainty in low-textured or reflective regions. We expect corresponding 3D points from different epochs to align more consistently in world space, enabling more reliable detection of subtle geomorphic adjustments like bar migration, scour-fill cycles, and/or sediment redistribution.

This study aims to demonstrate that sampling strategy and inference geometry are critical, yet previously overlooked, determinants of temporal repeatability in NeRF-based hydro-geomorphological monitoring. By replacing stochastic pixel sampling with deterministic grids and enforcing shared inference poses across epochs, we introduce a simple but potentially powerful modification that may enhance the reliability of NeRF-derived height/volume change estimates in dynamic river environments. The approach could open new possibilities for long‑term environmental and hydro-geomorphological research where spatiotemporal consistency is essential.

How to cite: Akwensi, P., Schulte, F., and Winiwarter, L.: Enhancing Multi-Temporal 3D Reconstruction of River Corridor Dynamics with Deterministic NeRF Sampling Strategies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12102, https://doi.org/10.5194/egusphere-egu26-12102, 2026.

Badlands are landscapes that develop on poorly consolidated bedrock under high erosion rates and their spatial distribution in Italy is related to marine clays outcrops. These landscapes are vulnerable to dynamic changes driven by geological processes, biological and anthropic factors at different spatial and temporal scales. This characteristic, along with the rapid transformation of landforms makes them ideal open-field laboratories, suitable for testing and improving means for predictive analysis. The study focuses on Badlands landscapes of the Basilicata region (Southern Italy) to explore the potential of the integration of different remotely-sensed data, from ground-based to satellite-based  technologies, in the definition of a probabilistic model for the evaluation of erosion trends. The integrative approach is essential for a comprehensive study of landscape dynamics, accounting for the complex interactions between top-down drivers (climatic and anthropogenic) and bottom-up drivers (biotic and geomorphological factors) of landforms evolution. In this perspective, Machine Learning (ML) techniques are effective tools for analysing the spatially heterogeneous responses of different morphologies in order to study their evolution and, therefore, their susceptibility to various processes (landslides, soil erosion). Maximum Entropy (MaxEnt) distribution models estimate a target probability distribution as a function of environmental predictors based on presence-only data. This approach has found several applications in the field of geomorphology, providing a more user-friendly and accessible way to perform studies based on statistical predictions. In contrast, MaxEnt has proven to be less robust in accuracy than other ML models. To overcome this issue while still guaranteeing accessibility, the study proposes the use of an advancement of the classical MaxEnt software called spatialMaxEnt, more sensible to the spatial distribution of data due to spatial cross-validation and a series of optimized functionalities to minimize overfitting. Presence data comprehends sites of occurrence of erosion processes identified through high-resolution topographic data within three study areas (Aliano, Tursi and Montalbano Jonico), externally grouped based on spatial autocorrelation, while environmental variables include topographic, climatic and anthropic attributes. A multicollinearity analysis using Pearson’s correlation coefficient is conducted prior to the MaxEnt modelling to identify and exclude highly correlated variables. This procedure ensures the selection of the most explanatory predictors and reduces the risk of model overfitting. The output data of the study is represented by Badlands susceptibility maps. This study further recommends comparisons with other AI-based models, as well as their possible combination, to enhance the robustness and significance of the results. Despite the challenges, the layers produced and the implementation of methodologies for modelling and identifying erosion-prone areas remains a fundamental tool for environmental monitoring and decision aimed at the conservation of the geological heritage.

How to cite: Santoro, G., Colacicco, R., Capolongo, D., and Marsico, A.: Integration of Remote Sensing techniques to assess badlands susceptibility in the Basilicata region (Southern Italy), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12111, https://doi.org/10.5194/egusphere-egu26-12111, 2026.

Large scale landslide susceptibility modelling (LSM) has rapidly evolved with the availability of large landslide inventories and high-resolution global environmental datasets. However, two fundamental issues continue to undermine the reliability and interpretability of such models: spatial autocorrelation (SAC) in landslide occurrences and strong feature redundancy (FR) among terrain-derived and environmental predictors. Although both factors are known to affect model outcomes, their relative and distinct impacts on predictive performance and model interpretability at large to global scales are still poorly disentangled. Here, we present a comparative modelling study aimed at systematically evaluating how SAC and FR differently influence large-scale landslide susceptibility models outcome. Using the UGLC (Unified Global Landslide Catalog, https://essd.copernicus.org/preprints/essd-2025-482/), which includes more than one million landslide records and an equal number of geomorphologically constrained non-landslide samples, we implement Random Forest (RF) models under three experimental settings: (i) conventional random train–test splitting, (ii) spatial k-means clustered train–test splitting to mitigate SAC-induced bias, and (iii) random train–test splitting combined with feature de-correlation to mitigate multicollinearity among 60 global geomorphological, hydrological, geological, and soil predictors. Our results show that random splitting leads to strongly optimistic performance (accuracy ≈ 0.96), dominated by spatial dependence between training and testing samples. When spatial clustering is applied, model performance decreases markedly (accuracy ≈ 0.82), exposing the true predictive capability under spatial independence. Feature de-correlation does not address SAC-related bias but produces measurable gains in robustness (accuracy ≈ 0.94), improving model interpretability across diverse climatic and geomorphological settings. These findings highlight that SAC and FR affect global LSM in fundamentally different ways. A spatial train–test splitting is indispensable for unbiased performance assessment, whereas feature de-correlation serves as a complementary strategy to enhance model stability and interpretability. This distinction is critical for the development of scientifically interpretable and operationally reliable global landslide susceptibility models.

How to cite: Capolongo, D., Mancino, S., and Amatulli, G.: Beyond optimistic accuracy: effects of spatial autocorrelation and feature redundancy in large-scale landslide susceptibility models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12758, https://doi.org/10.5194/egusphere-egu26-12758, 2026.

Accurate characterisation of nearshore bathymetry is crucial for modelling waves, monitoring hazards, and managing coasts. 

Ship-based technologies produce accurate bathymetry measurements but are expensive, time-consuming, and dangerous to use in relatively shallow coastal terrain, areas with rock outcrops, and intense waves. This results in a lack of bathymetry data in shallow coasts, creating a data void in nearshore zones. 

Several studies have used remotely sensed imagery for inverting nearshore bathymetry in shallow, homogeneous sandy coastal systems. However, existing empirical models often fail to estimate accurate bathymetry in energetic rock coast environments. To date, little or no attention has been placed on deriving nearshore bathymetry in rock coastlines due to high turbidity and heterogeneous bottom substrates. Empirical models do not perform effectively in determining nearshore water depth, which explains the greater focus on soft-coast systems and the neglect of rocky coastlines.

Multispectral (MS) optical sensors are preferred for bathymetry studies. The blue and green bands of the optical satellite image are limited in depth by turbidity, large waves, and currents. In contrast, Synthetic Aperture Radar (SAR) can track surface roughness and infer water depths in active waves and swells. By integrating passive optical and active SAR data, the limitations of relying solely on multispectral images to derive bathymetry in complex coastal areas can be overcome.

Rocky coasts are characterised by morphological heterogeneity that promotes increased turbulence under wave forcing. This affects light penetration and increases the complexity of optical water properties, reducing the accuracy of projected nearshore water depth using only optical sensors. While the western seaboard of Ireland is dominated by hard, rocky, cliffed coastline and extreme wave climates, it has a significant data gap in nearshore bathymetry.  

In a multi-sensor approach, this research used machine learning techniques to combine multispectral Sentinel-2 and Sentinel-1 SAR data with multibeam data to provide a comprehensive dataset for projecting nearshore bathymetry. This was carried out using supervised machine learning to train known depth values in a given coastal area, and unsupervised machine learning to predict unknown water depths in another nearshore zone. Projected water depth was validated using single-beam sonar data collected in Ballard Bay.

Random Forest, XGBoost, and LightGBM, techniques were used to train models. Models were then applied to generate nearshore bathymetry maps at three locations on the west coast of Ireland: Ballard Bay, Farrihy Bay, and Loop Head. The results indicated that Random Forest outperformed the XGBoost and LightGBM models across all sites, with R² values of 0.782, 0.765, and 0.740, respectively, with corresponding Root Mean Square Error (RMSE) of 0.578m, 0.698m, and 0.756m. A stacking ensemble model was built by combining the three models, which improved the R² for bathymetry prediction by 10% at all sites.

This research represents one of the first applications of machine learning–based nearshore bathymetry reconstruction focused specifically on rocky coastlines. The proposed ensemble method can produce precise bathymetric maps for nearshore areas across diverse regions and time periods. This will enable frequent assessment of rock coast evolution in relation to potential climate-driven impacts. 

How to cite: Arhin, M., Cullen, N., Hegarty, S., and Bourke, M.: Multi-Sensor Based Nearshore Bathymetry Projection in Rocky Coastlines Using Machine Learning Techniques, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13506, https://doi.org/10.5194/egusphere-egu26-13506, 2026.

The soil weathering rate of karst carbonate rocks is very low, resulting in scarce and thin soil layers. Under the subtropical monsoon climate, a well-developed epikarst zone is formed in the upper part of the vadose zone, with abundant fractures and pores filled with soil. The karst hillslopes surface bedrock is exposed, forming a mosaic soil landscape with soil.However, traditional profile surveys make it difficult to quantitatively determine the spatial distribution of soil and the epikarst zone with high precision; additionally, complex lithological conditions and strong spatial heterogeneity of carbonate rocks further limit the accurate quantification of soil thickness (ST) and epikarst thickness (EkT).

Therefore, this study investigated the soil-epikarst structures and their spatial distribution at different topographic locations (including different hillslope positions, ridges, saddles, and valleys) using Electrical Resistivity Tomography (ERT, 5268 sampling points) in a peak cluster-valley catchment in Southwest China. Furthermore, an interpretation method was established, where the application of revised inflexion points in 1D resistivity vertical profiles for improving ST and EkT characterization accuracy was assessed, with interpretations validated against borehole data.

Results showed that between hillslopes, the average ST ranges from 0.42 to 0.52 m, and the average EkT ranges from 3.38 to 4.58 m. The average ST in the valley (3.23 m) is significantly greater than that on hillslopes (0.49 m). Although there are some scattered, fragmented areas with EkT exceeding 20 m in the valley, both the average and median EkT in the valley (3.77 m and 2.98 m) are slightly smaller than those on hillslopes (3.93 m and 3.63 m).

This study integrated high-density ERT observations with a 1-m UAV LiDAR DEM and interpretable machine learning to predict karst soil and epikarst thickness. Important topographic controlling factors were screened out by machine learning, including those affecting ST (i.e., slope position (SP), relative elevation (RElev), slope gradient (S), slope roughness (SR), hillslope shape (HS), slope aspect (SOS), profile curvature (PrC)) and those affecting EkT (i.e., plan curvature (PLC), profile curvature (PrC), flow length (FLU), flow direction (FLD), aspect (A), relative elevation (RELE)).

Moreover, machine learning has made it possible to predict the spatial distribution of soil and the epikarst zone in the catchment with high precision, thereby providing structural information for studies such as soil erosion investigation, hydrological models, and material transport in porous media.

Keywords

Karst; Epikarst zone; Soil thickness (ST); Epikarst thickness (EkT); Electrical Resistivity Tomography (ERT); Machine learning; Southwest China

How to cite: Peng, T., Jiang, W., and Dai, B.: ERT and Interpretable Machine Learning Integrated Prediction of Karst Soil and Epikarst Thickness in a Peak Cluster-Valley Catchment, Southwest China, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15480, https://doi.org/10.5194/egusphere-egu26-15480, 2026.

Digital Elevation Models (DEMs) are a fundamental representation of terrain surfaces and are widely used in geomorphological analysis and terrain modeling. Traditional interpolation-based techniques are commonly used to address missing or unobserved regions in DEMs. However, these methods can struggle to recover coherent terrain structures when the gaps are large or irregular.

In this work, we investigate DEM completion by adapting model representations pretrained on large-scale image datasets to elevation data, which provides an effective initialization for Transformer models without requiring training from scratch. A Transformer-based architecture is employed to capture long-range spatial dependencies and global terrain structure, which are essential for reconstructing missing elevation regions. Geomorphological constraints are incorporated into the learning process to guide the reconstruction toward structurally consistent and physically plausible terrain surfaces.

Experimental results on a subset of the swisstopo DEM dataset demonstrate that the proposed approach achieves a mean absolute error (MAE) of approximately 6 m and a root mean squared error (RMSE) of approximately 11 m on the validation. Given that the average per-sample local topographic amplitude is approximately 256 m, an MAE of 6 m corresponds to less than 3% of this scale. The proposed approach leads to more coherent and structurally consistent DEM reconstructions compared to traditional interpolation-based methods, particularly in regions with missing or sparsely sampled elevation data. While the framework is developed for DEM completion, similar modeling principles could potentially be explored for other spatial surface reconstruction problems involving incomplete geospatial data.

How to cite: Lu, T., Jaboyedoff, M., Lin, R., and Wu, J.: Learning DEM Completion with Pretrained Spatial Representations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17529, https://doi.org/10.5194/egusphere-egu26-17529, 2026.

Bathymetric mapping of the Arctic seafloor remains challenging due to persistent sea ice, which limits systematic surveys and degrades multibeam echosounder (MBES) data through reduced swath width, ice interference, and vessel-induced noise. As a result, Digital Terrain Models (DTMs) derived from MBES data in ice-covered regions are often fragmented, coarse, and incomplete, obscuring bottom morphological features. These includes submarine glacial landforms that are informative of past glacier extents and ice-sheet dynamics. Standard interpolation is commonly used for upsampling and gap-filling but systematically oversmooths seafloor morphology, removing the small-scale variability central to glacial geomorphological interpretation.

Here, we investigate whether domain-informed generative super-resolution can recover geomorphologically meaningful structure in degraded Arctic bathymetry. We target upscaling from 100–200 m grid cell resolution to 25 m (4×–8×), with explicit emphasis on preserving glacial landforms rather than optimizing pixel-wise fidelity. We compile (i) 25 m MBES-derived bathymetry from surveys near northern Greenland and around Svalbard, which is downsampled to 100 m and 200 m to create controlled low-resolution inputs, and (ii) a larger set of terrestrial post-glacial Digital Elevation Models (DEMs) from Norway, Iceland, and the Hudson Bay region derived from airborne LiDAR and satellite products. The terrestrial DEMs provide a geomorphological prior without hydroacoustic artifacts and are used for training, while MBES data are reserved exclusively for evaluation in the Arctic bathymetry use case, acknowledging the domain shift between terrestrial and submarine environments.

We train a conditional diffusion model with a U-Net backbone to generate 25 m terrain conditioned on low-resolution inputs. In controlled downsampling experiments, conventional super-resolution metrics show limited separation from deterministic baselines; however, distributional similarity, quantified using the Wasserstein distance of elevation-value distributions, consistently improves. Qualitative assessments in regions such as Svalbard, Nares Strait, and Victoria Fjord show that the diffusion model produces sharper glacial lineations, more distinct retreat moraines, and clearer iceberg scour patterns than interpolation-based methods. To better quantify these geomorphological improvements, we introduce a Fourier-domain evaluation based on radial power spectral density and cross-correlation. Frequency-domain analysis shows that diffusion outputs more closely match the spectral characteristics of the 25 m reference data and tend to restore mid-wavelength power associated with glacial bedforms. Overall, the results suggest that domain-informed generative super-resolution can produce more interpretable bathymetric grids, while underscoring the need for evaluation metrics aligned with geomorphological realism.

How to cite: Matwiejczuk, J., Jasche, J., Mayer, L., Mohammad, R., and Jakobsson, M.: Diffusion-based Super-Resolution of Arctic Bathymetry for Glacial Geomorphology, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18865, https://doi.org/10.5194/egusphere-egu26-18865, 2026.

This abstract examines the role of Artificial Intelligence (AI) and Machine Learning (ML) in the geomorphological surveying of plunging cliffs, which represent some of the most dynamic and hazardous landforms on Earth. These steep and inaccessible environments are shaped by complex interactions between marine erosion, tectonics, weathering, and gravitational processes. Due to the complex logistics, traditional field-based surveying can be both risky and limited in spatial coverage. AI and ML techniques provide powerful tools to overcome these constraints by enabling the automated analysis of large, multi-source geospatial datasets, such as images, physical-chemical data, etc.

Data collected via swim surveys, drones, satellite imagery, and photogrammetry can be integrated into AI-driven workflows. Convolutional neural networks and other deep learning architectures can automatically detect coastal landforms, allowing detailed mapping of geomorphological features at unprecedented scales. Change detection algorithms applied to time-series datasets identify subtle deformation, rockfall precursors, and erosion patterns that may not be visible in the field or through manual interpretation. In parallel, ML-based classification and clustering methods help differentiate cliff characteristics, such as lithological units and surface conditions, improving the understanding of cliff geomorphic behaviour.

Overall, AI and ML can guide the transformation of plunging cliff geomorphological surveying from a largely manual and episodic practice into a continuous, high-resolution and, in the near future, predictive science. This approach not only enhances scientific insight into sea cliff dynamics but also provides practical tools for early warning systems, land-use planning, and the long-term management of these environments.

How to cite: Furlani, S.: AI and ML applications on plunging cliffs, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19667, https://doi.org/10.5194/egusphere-egu26-19667, 2026.

Artificial Intelligence is increasingly reshaping geomorphological research by enabling scalable, data-driven analyses of complex Earth surface processes. In this contribution, we present a supervised machine-learning framework for reconstructing Late-Quaternary coastal paleo-landscapes, applied to the rocky coasts of the Cilento Promontory (southern Tyrrhenian Sea), a tectonically quasi-stable sector preserving well-constrained sea-level indicators.
We trained a Random Forest classifier on an expert-labelled geomorphological dataset integrating DEM-derived morphometric parameters, lithology, distance from the coastline, and field-validated paleo-environmental markers. The model was developed within a fully reproducible workflow and validated against independent geomorphological mapping and sea-level proxy datasets.
Results demonstrate high classification performance and the ability to automatically discriminate between Last Interglacial paleo-sea cliffs and polycyclic, currently active coastal cliffs across different lithological contexts. The AI-based approach overcomes key limitations of traditional “bathtub” methods, allowing the detection of relict and partially buried landforms and extending paleo-landscape reconstructions into areas lacking direct field evidence.
Beyond the specific case study, this work illustrates how machine-learning approaches can be effectively integrated with geomorphological knowledge to reconstruct complex coastal paleo-landscapes. The proposed framework allows the identification of inherited and partially obscured landforms that are difficult to detect through traditional methods alone, offering a transferable tool for investigating long-term coastal evolution. This integration of AI and geomorphology provides new insights into the geomorphic response of rocky coasts to Quaternary sea-level fluctuations and climatic forcing.

How to cite: Sorrentino, A., Mattei, G., Pappone, G., Ciaramella, A., and Aucelli, P. P. C.: Machine learning–based reconstruction of Late-Quaternary coastal paleo-landscapes: an AI framework, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21186, https://doi.org/10.5194/egusphere-egu26-21186, 2026.

The accumulation of cohesive sediments is one of the most prominent issues in many tidal estuaries, as it has major implications on estuarine morphodynamics and on water quality and dredging strategies to support harbor activities. The work presented here focuses on the Gironde estuary, and more specifically on the Cadillac site located 40 km upstream of Bordeaux, where sediments were taken from the banks at low tide.

The first step was to characterise the physical properties of these materials by means of a granulometric analysis and rheological tests. Granulometric analysis (Mastersizer 3000, Malvern) is used to ensure the homogeneity of the sediments taken during the various campaigns. These reworked materials are then studied from a rheological point of view (HR2, TA Instruments) in order to identify in particular their yield stress for setting in motion. To do this, flow tests were carried out in a coaxial disc geometry in order to define the corresponding rheogram. The Hershel-Bulkley behaviour law is then applied to the descent curve to identify the yield stress. Once the protocol has been established, the effect of concentration is measured by diluting the sediments taken and the concentration is measured a posteriori by weighing the samples before and after drying. In this way, the law governing the evolution of yield stress as a function of concentration can be established.

Erosion tests were then carried out in a laboratory channel. The sediments were placed in the space left free between two ramps placed at the bottom of the channel. Initially, the threshold stress for setting the various samples in motion was established by gradually increasing the flow rate in the channel for a given height of water. The flow rate at which movement starts to occur on the sediment surface is noted. This flow rate is then translated into parietal stress on the bottom using PIV calibration on a rigid surface. It is assumed that the friction stress on the rigid bottom is equal to the minimum stress required to set the sediment in motion. These tests are repeated for different sediment concentrations. In a second phase, flows greater than the minimum flow are applied for 45 minutes and the quantity of sediment eroded is obtained by a double weighing method and by optical measurement using a 3D camera. In this way, the erosion rate, defined by the change in mass over time on a given reference surface, can be established and its evolution as a function of flow parameters and rheological properties can be determined. The final aim is to be able to propose an erosion law corresponding to the sediments of the Gironde estuary, which could then be used in numerical modelling.

This work was supported by the French National Agency for Research in the context of EMPHASE project (ANR-19-FQSM-0003).

This work pertains to the French Government program “Investissements d’Avenir” EUR INTREE, reference ANR-18-EURE-0010.

How to cite: Jarny, S., Salloum, G., Gomit, G., and Thomas, L.: Definition of an erosion law for cohesive sediments from Gironde estuary using rheology, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3485, https://doi.org/10.5194/egusphere-egu26-3485, 2026.

The erosion of riverbeds and banks in navigable channels controls the stability of the channel, the flow of sediment, and the maintenance of navigation depth. Understanding the erosion dynamics of natural sediments is crucial for predicting morphodynamical changes due to human-induced hydraulic influences.

This research examines the erosion characteristics of transitional fine to medium sand sediments from the Saône River (France), with the goal of establishing an empirical erosion law that connects hydraulic shear to sediment transport in these materials. Granulometric analyses revealed well sorted medium sand (D₅₀ ≈ 140 –160 μm), suggesting weak cohesion yet hydraulically mobile beds. Flume experiments performed under regulated flow conditions demonstrated a gradual onset of erosion within a flow rate range of 26–47 l/s, indicating that incipient motion takes place along a continuum rather than at a specific critical threshold. Time-dependent experiments indicated an initial period of quick detachment succeeded by a decrease in erosion rate, influenced by surface armoring and a depletion of the easily entrainable fraction. Dimensionless transport data were fitted using the Meyer-Peter and Müller (1948) and Van Rijn (1984) expressed respectively as Φ = 140.3(θ − 0.07)^4.43 and Φ =0.00153 d_∗^-0.3(θ/0.07 - 1)^4.43 with R² ≈ 0.74. The steep exponents highlight the nonlinear sensitivity of transport to excess shear stress, characteristic of transitional sediments. The derived relationships provide a quantitative foundation for predicting ship-induced erosion and sediment mobilization in navigable river systems.

This research was funded in whole or in part by the Agence Nationale de la Recherche (ANR) under project ANR-23-CE51-0032-01

How to cite: Salloum, G., Trujillo, D., Weingertner, F., Gomit, G., and Jarny, S.: Definition of an Erosion Law for Sediments of the Saône River, France, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3492, https://doi.org/10.5194/egusphere-egu26-3492, 2026.

Glacier-fed streams and their downstream ecosystems are influenced by bedload transport. An excess of bedload supply can lead to hazards, whilst an insufficiency can degrade in-stream habitats.  However, the processes by which bedload is mobilised and transported in such environments remain poorly understood, partly because its direct monitoring is challenging. Recent developments in micro-electromechanical systems (MEMS), particularly inertial measurement units (IMUs) for environmental applications, allow this gap to be addressed. Whilst IMU sensors have been primarily used for landslide and rockfall monitoring, their application to fluvial sediment transport is still emerging. Here, we use an innovative approach in which "smart rocks", rocks equipped with triaxial IMUs (accelerometers, gyroscopes, and magnetometers), are deployed in an Alpine proglacial environment. In combination with wireless data transmission, they can be described as “smart” as they can collect data autonomously and transmit it over quite long distances, via Long Range Wide Area Network (LoRaWAN) technology, which allows near real-time communication.

This work presents preliminary results from field tests conducted in autumn 2025 in the proglacial forefield of the Bas Glacier d’Arolla (Swiss Alps) in order to assess their applicability in a realistic alpine environment and to evaluate their potential for capturing bedload transport. Detailed results of a single particle during the flushing of hydropower infrastructure allow quantification of the forces associated with particle entrainment, transport, and resting phases. Central to the method are issues associated with data transmission and particle traceability. However, this preliminary work already demonstrates the potential of smart rocks as a promising tool for improving our understanding of bedload transport in alpine environments, especially for understanding sediment transport processes at the individual particle scale.

How to cite: Hofmann, M., Roskilly, K., Bennett, G., and Lane, S. N.: Using smart rocks to improve understanding of bedload transport in a proglacial forefield, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7831, https://doi.org/10.5194/egusphere-egu26-7831, 2026.

Luminescence is now used to date the exposure of rocks at the Earth’s surface or to measure their erosion rates. These methods are based on the observation that the luminescence of a rock exposed to sunlight is not only reset (bleached) at the surface but also at depth below the surface. For a stable surface, this bleaching depth (PBl) increases over time, forming a “bleaching front” that propagates into the rock interior. For an eroding surface, models show that a balance establishes between erosion and bleaching, and that PBl then depends on the erosion rate. Here, we present luminescence measurements performed on pebble surfaces sampled along a river in order to assess whether longitudinal variations in PBl could be used to quantify pebble transport durations or their abrasion (attrition).

Our study focuses on the Ardèche River (France), a ~120 km long river which is a tributary of the Rhône River. In its headwaters, in the Cévennes (french Massif Central), the eroded bedrock consists of Paleozoic metamorphic and plutonic rocks (including granites) and Quaternary volcanics. Then, along most of its course (~ 90 km) the river flows and cuts into Mesozoic carbonates. In its downstream end, it forms a  ~200 m deep and 30 km long gorge (“Gorges de l’Ardèche”), before connecting to the Rhône.

We consider here the luminescence of pebbles and cobbles sampled on twelve site along the Ardèche modern floodplain. For this purpose, we first characterized the granulometric distribution of alluvial bars on the 12 sites and then sampled granitic cobbles considering the D50 and D90 of the distributions.

Luminescence profiles (IRSL) of granite pebbles show PB1 depths ranging between 2 and 10 mm. For the D50 fraction, the luminescence signal reflects a progressive downward deepening of PB1, from the upstream area to the entrance of the gorges. Within the gorges, a slight reduction in PB1 depth is observed that we attribute to enhanced pebble abrasion within the gorges. Our results suggest that luminescence could form the basis of a new method for investigating the transport and abrasion of pebbles in fluvial systems.

How to cite: Allebe, M., Brill, D., and Bonnet, S.: Evaluation of luminescence techniques for investigating the transport and abrasion of pebbles in fluvial systems: the Ardèche River (France), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9287, https://doi.org/10.5194/egusphere-egu26-9287, 2026.

Lateral channel mobility is a key process controlling the morphodynamic evolution of large gravel-bed rivers, yet it remains difficult to represent numerically because of the strong coupling between flow hydraulics, sediment transport and bank erosion. This communication presents a data-driven approach for morpho-sedimentary model calibration, based on several complementary research articles derived from extensive field measurements and combining dense field instrumentation with a rich multi-sensor dataset to constrain detailed numerical models.

The proposed framework is applied to the morphodynamic modelling of an actively migrating meander of the Moselle River (north-eastern France), located within the Wild Moselle regional nature reserve. A multi-year field monitoring program included topo-bathymetric LiDAR surveys, water level records, ADCP velocity measurements, photogrammetric monitoring of bank erosion, direct (in situ) and indirect (hydrophone) bedload measurements, and particle mobility analyses using painted bed patches and RFID tracers.

A high-resolution 2D hydro-sedimentary model was implemented using TELEMAC-2D coupled with SISYPHE to investigate the processes governing meander dynamics. Model parameterization was constrained by in situ measurements, enabling the reproduction of observed flow patterns, sediment transport and bank erosion processes. Particular attention was paid to the contribution of bank-derived sediments to bedload transport and their role in channel morphodynamic.

Results show that the morpho-sedimentary model is capable of reproducing observed bank retreat, highlighting the potential of data-constrained two-dimensional approaches to represent inherently three-dimensional erosion processes. This modelling framework provides a robust basis for assessing future channel evolution and for exploring river management scenarios addressing lateral channel mobility and associated risks to infrastructure destabilization.

How to cite: Piasny, G., Garambois, P.-A., and Schmitt, L.: A data-driven framework for calibrating 2D morpho-sedimentary models in gravel-bed meandering rivers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11075, https://doi.org/10.5194/egusphere-egu26-11075, 2026.

Sediment transport is a fundamental process governing river hydraulics and channel morphology. During hyperconcentrated flows and flooding events, conventional optical and in situ sampling techniques are often unable to capture sediment transport behavior continuously. Previous studies have shown that contact-based hydroacoustic measurements can capture acoustic signals generated by particle impacts on the riverbed and enable continuous observations under high stream power conditions (Geay et al., 2017). However, contact-based hydroacoustic sensors are vulnerable to damage during flood events, resulting in high maintenance costs. To address this limitation, this study develops a low-cost, autonomous hydrophone system capable of continuous hydroacoustic recording. The system was tested in a large-scale field artificial channel constructed along the Landao Creek at Huisun Forest Station, Taiwan, where controlled discharges supplied from the upstream Nenggao Main Canal enabled experiments under dry-bed, steady-flow, and flood-peak conditions. To assess the performance of the autonomous hydrophone, a multi-physics sensing framework was established by synchronously deploying the hydrophone, a distributed acoustic sensing (DAS) system, and a microseismic sensor (SmartSolo). Under identical hydraulic and sediment supply conditions, hydroacoustic, ground vibration, and fiber-optic strain-rate signals were simultaneously recorded and analyzed to infer sediment transport behavior and riverbed activity. For data analysis, power spectral density (PSD) was employed as the primary frequency-domain method to analyze band-limited energy variations using a moving-window approach. In addition, waveform clipping events were detected and statistically analyzed to further identify high-energy transient events, which were used as an auxiliary indicator of bedload activity. The results indicate that the autonomous hydrophone reliably captures acoustic signatures associated with sediment transport and exhibits strong consistency with DAS strain-rate and microseismic observations, demonstrating its potential for integrated sediment transport monitoring in controlled artificial channel experiments.

Keywords: sediment transport; low-cost autonomous hydrophone; fiber-optic strain rate; microseismic signals

How to cite: Chen, B.-Y. and Chao, W.-A.: A Low-Cost Autonomous Hydrophone System Integrated with Multidisciplinary Observations for Sediment Transport Monitoring in a Large-Scale Field Artificial Channel, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11627, https://doi.org/10.5194/egusphere-egu26-11627, 2026.

The movement of bedload sediment results from episodic grain motion involving hops and rests
controlled by hydrodynamic forces and collisions with the bed surface. Despite extensive research
studying the velocity distributions, there is no firm consensus regarding particle-scale dynamics,
particularly whether velocity distributions exhibit exponential-like or gamma-like characteristics.
In this work using high-resolution LES–DEM simulations, we investigate how observational
thresholds and flow conditions shape grain motion statistics. Our results demonstrate that velocity
threshold choices critically affect the observed distributions as including low-velocity events
produces exponential-like streamwise (v_x) and Laplace-like cross-stream (v_y) velocity distributions,
while filtering these events yields gamma and Gaussian forms. The streamwise velocity
distribution maintains its exponential character across flow intensities, but cross-stream
distributions evolve from Gaussian to Laplace-like as turbulent forcing strengthens. Fine-scale
analysis of velocity–acceleration phase space exposes highly asymmetric acceleration signatures
controlled by impact-driven collisions, whereas coarser temporal averaging generates symmetric
patterns. Hop distances exhibit Weibull-type distributions with stable scale factors, while the
relationship between hop length and duration transitions from quadratic to linear dependence
across all flow regimes, revealing inherent scale-dependent transport mechanisms. Throughout the
investigated conditions, bedload transport rates increase predominantly via nonlinear growth in the
number of mobile particles (particle activity), with mean particle velocities showing minimal
variation. These findings reconcile contradictory literature on bedload kinematics, emphasizing the
dominant role of particle mobilization dynamics, and reveal how measurement protocols introduce
systematic biases in grain-scale statistical characterization.

How to cite: Yadav, A. and Glade, R.: Temporal Resolution Controls on Ensemble Statistics of Bedload Transport, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12030, https://doi.org/10.5194/egusphere-egu26-12030, 2026.

In this work, we employ Global Sensitivity Analysis (GSA) to quantify the robustness of sediment fluxes and sediment budgeting simulated at the river network scale. These simulations are subject to significant uncertainties when determining key drivers of transport capacity estimation, such as active transport width, river slope, or grain size distribution. These parameters, already difficult to estimate accurately at the scale of individual river cross-sections, become even more challenging to constrain at the network or entire river scale.  

We achieve this by applying the network scale sediment transport model, D-CASCADE (Dynamic CAtchment Sediment Connectivity And DElivery), to the 528 km long Po River basin in Northern Italy. D-CASCADE divides a river network into discrete units, termed ‘reaches’, and uses an empirical sediment transport formula to estimate how sediment is transported through this network. The river Po was divided into 35 reaches of homogenous geomorphic characteristics of a few kilometers each, and the model includes the input from 21 of its main tributaries.  We simulated the sediment transfer across this network for five hydrological years (2017-2021), with a daily time step.

Monte Carlo simulations were conducted using 1000 realizations, jointly perturbing the nominal value of 9 input parameters, such as active transport width, slope, roughness coefficient, and initial grain size distribution (GSD), for all the 35 reaches composing the Po River course. Specifically, the proposed methodology aims at assessing whether the plausible variations of the input parameters (that we established from field data and expert judgement) affect the nature of a river reach in the simulations, as sediment source (negative sediment budgeting), sink (positive sediment budgeting), or at equilibrium (sediment budget under a threshold), hence impacting its geomorphic behavior. The results indicated a strong robustness in classification, as no transition from source to sink was observed in any reach in the network. Nonetheless, some reaches shifted from being classified as either source or sink to

Regional Sensitivity Analysis (RSA) was then applied to identify which uncertain parameters have the greatest influence on such transitions. The RSA results showed that the active width, slope, roughness coefficient, and active layer depth are the primary input parameters affecting the river's state in gravel-dominated reaches, while the initial grain size distribution (GSD) is important in its sand-dominated reaches.

The presented approach applied to such network models allows for testing whether modelled river reaches maintain similar geomorphic behaviour despite the input uncertainties, while also identifying river network segments that exhibit an increased sensitivity and to which parameters. These insights can help prioritize efforts in data collection (known to be resource and time-demanding) and/or guide model calibration (known to be computationally expensive) towards parameters and locations whose improvements would most effectively reduce the final model uncertainty.

How to cite: Shrestha, S., Pianosi, F., Bozzolan, E., Doolaeghe, D., Surian, N., and Bizzi, S.: Are the source and sink behaviour simulated by a network-scale sediment transport model credible?  , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13574, https://doi.org/10.5194/egusphere-egu26-13574, 2026.

Being a country with heavy monsoon rains and seasonal flooding, every year Bangladesh faces severe damage, some of which are irreparable. The flood of 2024 which occurred in August, severely affected the north-eastern and south-eastern part of the country. Feni district was severely affected because of heavy water flow from the Dumboor dam in Tripura state. Subsequently, bringing massive amount of sediment load through the hilly area. These flooding events cause significant damage to human life in the region, the flood-associated sediment is also crucial for the region's agriculture. Therefore, the purpose of this study was to find the amount of sediment deposited due to the flood in the Feni floodplain. To achieve this objective, interferometry methods were used to create the Digital Elevation Models (DEMs) of the floodplains before and after the flood. To analyze the flood-plain state before the flood, two images were selected from 29th May to 10th June and two images were selected after the flood between 8th to 20th October. Single Look Complex (SLC) products were chosen, which consist of focused SAR data, geo-referenced using orbit , attitude data from the satellite and provided in slant-range geometry. The Sentinel-1 images were pre-processed . Than phase was unwrapped, and converted to DEM. The software SNAP, which is a common architecture of all Sentinel toolboxes, was used for DEM generation. After the DEM generation, 8 profiles were drawn to observe the change in topography due to sedimentation by HEC-RAS software. It was found that there was an average of 2.7 cm sediment deposition throughout the region and a 7.5 cm maximum deposition.

How to cite: Jahib, A. A., Fardin, M. A. G., and Khan, S. M.: Post-Flood Sediment Deposition Analysis Using SAR Interferometry: A Case Study of the 2024 Flood in Feni district, Bangladesh, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13958, https://doi.org/10.5194/egusphere-egu26-13958, 2026.

Catastrophic sediment release in fluvial systems is largely driven by landsliding that occurs naturally in mountain belts during extreme events, such as earthquakes or storms. Sediments are routed through the river system until they are stored either permanently in alluvial fans and lakes or temporarily in floodplains. The river response to such catastrophic sediment release has already been studied with 2D numerical models using a single effective grain size. Yet, in natural systems, sediment grain-size distributions can span several orders of magnitude and evolve during transport.

We present the new multi-grain-size sediment transport and sorting model SEDSCAPE (Sediment Entrainment Deposition and Storage based on the Concepts of Accessibility and Partial Equilibrium). This model was developed to predict how sediments of heterogeneous sizes that originate from landslides triggered by extreme events such as earthquakes and storms propagate through a river system. As modelling the 3D response of a river reach is computationally challenging, we couple SEDSCAPE with STRIMM (Lague, 2010), a model of river width evolution, to provide a simplified 2.5D approach. In turn, we can predict both morphodynamic changes and the full spectrum of sediment fluxes towards the floodplain and at the river outlet, and thus the sedimentary records in these locations.

We conducted numerical simulations of a constricted river reach consisting of a straight channel with floodplains on both sides. A time series of sediment and water discharges was applied to predict the response of a river reach affected by a landsliding event over several months to years. For comparison purposes, similar simulations were conducted with a single grain size.

Numerical simulations reveal: i) how different levels of sediment mobilization (water discharge) control sediment sorting processes and in turn sediment fluxes, ii) how the grain-size specific signals propagate in a river reach and are preserved in the channel and floodplain stratigraphy in response to a catastrophic sediment release, and ii) how the channel width adjusts with stochastic flow conditions and sediment supply.

The comparison between single- and multiple-grain-size simulations highlights the relevance of the multiple-grain-size approach to predict the response of a river reach to a catastrophic sediment release. Indeed, only the multi-grain-size approach is able to capture the hysteresis of transport, and different hysteresis patterns are obtained depending on the grain size as they have heterogeneous levels of mobilization and are not affected by sorting processes in the same way.

These results were obtained in the context of the SCALEES (Signature of sediment CAscades following Landslides triggered by Extreme Events in the Stratigraphy) project funded by the European Union. One key outcome of this project is the development of numerical models that will allow us to predict the full signal (all grain sizes) of sediment cascades preserved in stratigraphy in response to an extreme event. It will also pave the way for inverting the stratigraphic record of landslide-induced sediment cascades for quantitative insights into their response amplitudes and relaxation times.

How to cite: Le Minor, M., Lague, D., Howarth, J., and Davy, P.: Application of a coupled model of channel width evolution and multi-grain size sediment transport to predict the full signal (all grain sizes) of sediment cascades preserved in stratigraphy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15663, https://doi.org/10.5194/egusphere-egu26-15663, 2026.

Sediment entrainment thresholds in rivers have been widely studied, informing the prediction of bedload transport rates that underpin morphodynamic modelling. However, quantification of sediment entrainment in complex channels with varying degrees of bedrock exposure and sediment cover remains limited. Here, physical modelling was conducted to simulate a 1:10 scaled model of a bedrock reach from the River Garry in Scotland. Sediment entrainment thresholds were measured for isolated grains corresponding to selected percentiles of the bed grainsize distribution (D₁₀, D₅₀,  D₉₀) over a bedrock surface with five sediment cover percentages (0, 25, 50, 75, 100%). Bed roughness metrics (e.g. standard deviation of bed elevation) of each bed were calculated. Sediment entrainment was found to be modulated by the bed roughness, resulting from the bedrock topography and infilling of depressions with sediments. Particle tracking revealed the spatial transport of sediment grains, along with the influence of localised bed roughness features on sediment dynamics.

How to cite: Houseago, R., Hodge, R., Norris, W., and Inoue, T.: Sediment transport in rough bed rivers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19732, https://doi.org/10.5194/egusphere-egu26-19732, 2026.

Coastal systems are highly dynamic environments where sand and mud are transported under the complex interactions of bathymetry, currents and waves. A better understanding of the natural dynamics at the scale of individual bars is required for a fundamental understanding of the formation of coastal environments and how they will respond to changes in the future. However, many coastal environments consist of spatially varying mixtures of sand and mud, while current sediment transport predictors and empirical relations of bar dynamics do not take into account the effect of cohesive sediment. The current research therefore aims to characterize the relative influence of clay on the direction of sediment transport and the resulting morphodynamic change of coastal bars under the combined action of waves and currents.

To this end, experiments were conducted in the Total Environment Simulator, a large-scale wave-current flume facility at the University of Hull (6m x 11m, 0.4m deep). The experimental setup consisted of a circular mound of a mixture of sand and clay, placed on top of a flat sand bed in the centre of the flume. The experimental conditions were systematically varied between runs, with 4 different clay percentages of the mound, and 5 different combinations of wave height and current velocity, while keeping the total bed shear stress constant. Flow velocity, water level and bed levels were monitored during each run, and the bed was scanned before and after each experiment.

Observations of the mound morphology show lateral diffusion due to sediment transport perpendicular to the wave direction under the influence of gravity, and streamwise migration due to sediment transport in the direction of the flow. Increasing the cohesivity altered the relative influence of the waves and currents on the direction of sediment transport and therefore the final shape of the mound. With increasing clay content, relatively more lateral and less streamwise transport occurred under the same hydrodynamic conditions. Furthermore, wave height had a greater control on the morphology with increasing clay content, since higher waves were more effective in winnowing out the clay into suspension and thereby mobilizing the sand fraction. These results imply that coastal and estuarine environments with spatially varying clay content will adapt differently to changing hydrodynamic conditions. In systems with a relatively high clay content, wave energy will have an important control on dynamics as it is needed to mobilize the sediment.

How to cite: Baar, A., Murphy, B., McLelland, S., and Parsons, D.: Cohesive sediments alter coastal bar dynamics under waves and currents, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22274, https://doi.org/10.5194/egusphere-egu26-22274, 2026.

High-relief great escarpments are prominent geomorphic features characterizing many passive continental margins, extending for hundreds to thousands of kilometers subparallel to the continent-ocean boundary and connecting coastal plains with upland plateaus. Initial formation of these escarpments is most often attributed to oceanic rifting preceding passive margin development. However, in many cases, including our study area in SE Australia, these escarpments have persisted for tens to hundreds of millions of years after rifting, raising questions about their geomorphic origin and evolution. One of the challenges to understanding the evolution of great escarpments is that erosion-driven exhumation produced during their retreat from the coast is expected to be too small in magnitude to be recorded by conventional thermochronometers, such as apatite fission track (AFT). Here, we present apatite ⁴He/³He thermochronology results from a bedrock transect across the SE Australian escarpment. Existing AFT and conventional (U-Th)/He data in SE Australia appear to lack sufficient resolution to fully document the timing of cooling associated with escarpment retreat. Apatite ⁴He/³He thermochronology, on the other hand, is sensitive to temperatures as low as 35 ºC, making it suitable for detecting cooling signals from the estimated 1-1.5 km total exhumation associated with escarpment retreat in this region. Preliminary thermal history models based on our initial apatite ⁴He/³He data document an increase in cooling rates across the coastal plain ca. 120-80 Ma. This late Cretaceous signal overlaps with the initiation of rifting of the Tasman Sea and is consistent with a plateau degradation style of escarpment evolution, where the escarpment formed and retreated to near its present-day position rapidly after rifting. Ongoing acquisition of additional apatite ⁴He/³He data will allow us to further assess the extent of late Cretaceous cooling along the coastal plain and better constrain landscape evolution models of escarpment development.

How to cite: Zhan, W., Gong, L., Tremblay, M., Curry, M., and McMillan, M.: Post-rift evolution of the southeastern Australia Great Escarpment from apatite 4He/3He thermochronology, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-565, https://doi.org/10.5194/egusphere-egu26-565, 2026.

The dynamic Cape south coast of South Africa is widely recognised for its extensive occurrence of aeolian coastal dunes and older (cemented) aeolianites; the latter are thought to preserve records of dune formation spanning multiple glacial-interglacial cycles. However, existing records are dominated by Marine Isotope Stages (MIS) 1 and 5e ages. Extensive and (assumed) much older deposits have been identified, but are largely unstudied. By reconstructing their chronologies, we aim to generate new insights into coastal change during the Early to Middle Pleistocene and examine the factors that control long-term preservation of aeolianite deposits on a tectonically stable coastline. We anticipate preservation to be largely influenced by local topography and underlying geology.

Here we focus on the geomorphic history of Walker Bay, southwest of Cape Town. Our aim is to integrate a suite of geophysical (ground penetrating radar-GPR), geochemical (ICP-MS, SEM) and luminescence (TT-OSL (quartz) and post-IR-IRSL (K-feldspar)) dating methods to unravel the chronology, structure and provenance of dune sands within the embayment. 

Initial results indicate an age range of ~1 million years to ~600,000 years. The applied methods TT-OSL, IR225, and IR290 show some results that are close to each other, while others vary outside the error range. We also observe several unusual aeolian deposits, some of which are far from the modern coastline and reach elevations of more than 250m above sea level (amsl). Other locations with closely juxtaposed aeolianites (dating to >600ka), substantially greater than any yet published for this coastline, and uncemented sands (late Pleistocene) dated to MIS-3, a period with fewer records & sea-levels were significantly lower than present. The results challenge existing models, which suggest that pulses of dune formation occurred primarily during the MIS-5 and MIS-1 highstands. Several questions arise as to the mechanisms of aeolianite formation/preservation at such heights and distances relative to the modern coast, and the results present further questions: Is Walker Bay Unique? Or are such complex suite deposits much more widespread? On this basis, we consider whether methodological and sampling limitations have led to a spatio-temporal biased record of long-term dune formation in this region. Or is it a completely different system than what has been observed on the coast before?

How to cite: Borde, H., Carr, A., Cawthra, H., and Cowling, R.: Extending the record of coastal aeolian landscape change into the Middle and Early Pleistocene: a multi-method comparison SAR-OSL, TT-OSL and post-IRIR, Walker Bay, South Africa, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-641, https://doi.org/10.5194/egusphere-egu26-641, 2026.

The geomorphological evolution of landscapes is primarily governed by the coupled influence of tectonics and climate, with their relative dominance varying through time and space. In the Ladakh Himalaya, where active deformation intersects pronounced Quaternary climatic fluctuations, this coupling produces a distinct geomorphic signature. The Muglib Valley, formerly the outlet of Pangong Tso, demonstrates a system in which tectonic forcing initiated hydrological reorganisation, subsequently amplified by climatic variability. The region lies along the Karakoram Fault system, where oblique right-lateral slip with a vertical component (3–5 mm yr⁻¹) has modified basin geometry, offset valley alignments, and generated localised blockages that facilitated lake formation. Detailed geomorphic and sedimentological analyses across seven field sections reveal marked spatial variability: stacked gravels and conglomerates represent sustained fluvial aggradation, while thick fan and lacustrine deposits reflect progressive sediment overloading and hydrological stagnation, respectively. Optically Stimulated Luminescence (OSL) ages indicate a steady flow of water from Pangong Tso between ~54 ± 4.3 ka and 21 ± 3 ka. Thereafter, the channel was cut and eventually abandoned at ~9 ± 1 ka. The latter coincides with intensified monsoonal precipitation during the Holocene Climate Optimum, which enhanced sediment flux and triggered fan progradation, ultimately blocking the Muglib outlet. This geomorphic transformation converted Pangong Tso from an open to a closed basin, isolating an upstream catchment of ~2000 km² and terminating water and sediment supply to the Tangste River. The findings demonstrate that slow but persistent tectonic activity along the Karakoram Fault primarily governed drainage reorganisation, while monsoon intensification acted as an additive trigger that accelerated fan aggradation and hydrological isolation. The Muglib system thus provides an example of coupled tectonic–climatic feedback that has reshaped the fluvial architecture and sediment connectivity in the Trans-Himalayan landscape.

How to cite: Sagwal, S., Kumar, A., Srivastava, P., Saha, S., and Shahrukh, M.: Open to closed basin: tectonic and climatic feedback in the evolution of the largest Himalayan lake system , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-675, https://doi.org/10.5194/egusphere-egu26-675, 2026.

The geomorphic and sedimentological evolution of the dynamic Satluj River basin is understood through a detailed analysis that combines comprehensive morpho-sedimentary mapping, lithofacies analysis, and optically stimulated luminescence (OSL) dating to evaluate the impact of base-level fluctuations. Although the valley is far from the current coastline, evidences of minor changes in base level caused by climate and sea level processes reach deep into the hinterland is clearly seen in such a dynamic mountain catchment of the Himalaya. These changes majorly control river dynamics, sediment transport, and overall landscape evolution. Frequent landslides, temporary channel damming, lake formation, and large fluvio-lacustrine sedimentary successions direct periods of enhanced sediment input and aggradation. Morphotectonic indices and the presence of seismites in these deposits suggest significant tectonic influence on base-level-driven geomorphic responses.

Optical chronology identifies two major aggradation phases: one from about 30 to 24 ka and another from about 17 to 11 ka. During these phases, more sediment was deposited, less material was transported, and the local base level temporarily rose owing to valley damming. In these periods, the landscape was unstable, resulting in numerous mass-wasting events, the creation of dammed palaeolakes, and the preservation of extensive sedimentary records. Subsequent incision stages form strath terraces, vertically incised gorges, offset channels, and modifications in the shape of Quaternary sediments. This indicates that the base level declined again and tectonic activity resumed.

The observed relationship between aggradation-incision cycles, dammed lakes, and tectonically influenced base-level fluctuations demonstrates how climate-driven base-level modifications can be greatly amplified in dynamic mountain belts. The findings suggest that base-level signals connected to sea-level fluctuations may have an indirect impact on sedimentation and geomorphology over significant distances upstream through complex sediment-routing systems. This study adds new constraints on late Quaternary catchment-scale geomorphic adjustment and improves understanding of how sea-level-induced base-level changes interact with tectonics, landslides, and fluvial processes to shape the Himalayan landscape.

How to cite: Shahrukh, M. and Kumar, A.: Propagation of Base-Level Signals into an Active Himalayan Catchment: Morpho-Sedimentary and OSL Evidence from the Satluj River Valley, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-730, https://doi.org/10.5194/egusphere-egu26-730, 2026.

The deglaciation history of the European Alps is thought to be well established, however, the timing of glacier retreat in the eastern Alps remains poorly constrained. Here, we present the first ¹⁰Be exposure ages from the Klagenfurt Basin (Carinthia, Austria), which was covered by the piedmont lobe of the Drau glacier during the Last Glacial Maximum (LGM). The ¹⁰Be ages were obtained from glacially polished quartz veins between ~530 and ~800 m a.s.l. and range from 17.4±0.6 to 13.5±0.7 ka (mean age: 15.9±1.0 ka). The age data indicate that deglaciation of the Klagenfurt Basin occurred near the end of the Oldest Dryas stadial and are consistent with published ¹⁰Be ages from the flat tops of the ~2000-m-high Nock Mountains farther north (mean age: 15.0±1.2 ka) (Wölfler et al., 2022). Both data sets refute a widely accepted scenario, in which the southeastern Alps were already ice-free by ~19-18 ka (e.g., van Husen, 1997; Reitner, 2007; Ivy-Ochs et al., 2023). Our reassessment of the underlying age constraints for this still prevailing view shows that the respective ¹⁴C ages were obtained from bulk-sediment samples in two postglacial lakes (Lake Längsee: Schmidt et al., 1998, 2002; Lake Jeserzer See: Schmidt et al, 2012). ¹⁴C ages from bulk lake-sediment samples are, however, known to overestimate the true sedimentation age due to a reservoir effect (e.g., Ilyaschuk et al., 2009; Hou et al., 2012). At Lake Längsee, the overestimation of the true sedimentation ages by the ¹⁴C ages is confirmed by a layer of Neapolitan Yellow Tuff, whose age was independently determined by ⁴⁰Ar/³⁹Ar dating at its origin (Deino et al., 2004). Later deglaciation than previously assumed is further supported by two published ¹⁰Be age data sets from the Hohe Tauern mountains, which indicate LGM ice-surface lowering between ~18.6 and ~14.8 ka (Wirsig et al., 2016) and rock-glacier stabilization at ~16-14 ka (Steinemann et al., 2020), respectively. Our interpretations agree with palaeo-precipitation records derived from cave carbonates, which indicate enhanced autumn and winter precipitation during the LGM and until ~17 ka (Spötl et al., 2021; Warken et al., 2024). The combined evidence presented in our study shows that deglaciation of the southeastern Alps occurred at ~16-15 ka and hence later than previously thought.

References

Deino et al., 2004, J. Volcanol. Geotherm. Res., 133, 157–170, doi.org/10.1016/S0377-0273(03)00396-2.

Hou et al., 2012, Quat. Sci. Rev., 48, 67–79, doi.org/10.1016/j.quascirev.2012.06.008.

Ilyaschuk et al., 2009, Quat. Sci. Rev., 28, 1340–1353, doi.org/10.1016/j.quascirev.2009.01.007.

Ivy-Ochs et al., 2023, In: European Glacial Landscapes—The Last Deglaciation, 175–183, doi.org/10.1016/B978-0-323-91899-2.00005-X.

Reitner, 2007, Quat. Int. 164/165, 64–84, doi.org/10.1016/j.quaint.2006.12.016.

Schmidt et al., 1998, Aquat. Sci. 60, 56-88.

Schmidt et al., 2002, Quat. Int., 88, 45–56.

Schmidt et al., 2012, J. Quat. Sci. 27, 40–50. doi.org/10.1002/jqs.1505.

Spötl et al., 2021, Nature Commun. 12, 1839, doi.org/10.1038/s41467-021-22090-7.

Steinemann et al., 2020, Quat. Sci. Rev. 241, 106424, doi.org/10.1016/j.quascirev.2020.106424.

Warken et al., 2024, Comm. Earth Environ. 5, 694, doi.org/10.1038/s43247-024-01876-9.

Wirsig et al., 2016, Quat. Sci. Rev. 143, 37–50, doi.org/10.1016/j.quascirev.2016.05.001.

Wölfler et al., 2022, J. Quat. Sci., 37, 677–687, doi.org/10.1002/jqs.3399.

How to cite: Hampel, A. and Hetzel, R.: Deglaciation of the Klagenfurt Basin (Austria): constraints from 10Be exposure dating and implications for the glacial history of the southeastern Alps, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1613, https://doi.org/10.5194/egusphere-egu26-1613, 2026.

The uplift of the Rhenish Massif is recorded by strath terraces along major rivers, however, absolute age control for the terraces is still scarce, and terrace correlations with Quaternary climate cycles are uncertain and partly contradictory. Along the Rhine, two terrace levels – the Older and Younger Main Terrace (OMT and YMT) – occur above a marked break-in-slope, which separates a steep lower valley from a broad upper valley with gentle slopes. Based on limited paleomagnetic data, an age of 730–800 ka for the YMT was often assumed and used to estimate rock uplift (e.g., Meyer & Stets, 1998). Here, we present the first ¹⁰Be – ²⁶Al isochron-burial ages for the OMT and YMT at two sites: Kasbach-Ohlenberg and Bad Hönningen. At Kasbach-Ohlenberg, the OMT yields a burial age of 1.4–1.6 Ma, while the YMT is dated to 0.7–0.8 Ma. These ages and the small vertical distance of only a few meters between both terraces indicate a prolonged period with little river incision, followed by a phase of more rapid incision and rock uplift. The elevation of the bedrock strath of the YMT above the Rhine (i.e., ~160 m) implies an average uplift rate of ~200 m/Ma during this phase. At Bad Hönningen, the OMT yields a burial age of 1.1-1.4 Ma. This younger age and the higher elevation of the OMT at this site suggest that rock uplift increases toward the internal part of the Rhenish Massif. The temporal coincidence between the onset of uplift and plume-related intraplate volcanism in the Eifel at ~700 ka (e.g., Lippolt et al., 1983) suggests a mantle-driven origin for the uplift. Our ongoing work will result in additional age–elevation data for terrace sites along the Rhine, thus enabling a more detailed reconstruction of the timing, rate, and spatial variability of uplift in the Rhenish Massif.

References
Lippolt, H.J., 1983. Distribution of volcanic activity in space and time. In: Fuchs, K., von Gehlen, K., Mälzer, H., Murawski, H., Semmel, A. (Eds.), Plateau Uplift. Springer, Berlin, pp. 112–120.
Meyer, W., Stets, J., 1998. Junge Tektonik im Rheinischen Schiefergebirge und ihre Quantifizierung. Z. dt. geol. Ges. 149, 359–379. https://doi.org/10.1127/zdgg/149/1998/359.

How to cite: Terraza, M., Wolff, R., Hetzel, R., Ritter, B., Binnie, S., Preuss, J., Hoselmann, C., Weidenfeller, M., and Heinze, S.: Accelerated uplift of the Rhenish Massif (central Europe) since 700–800 ka revealed by isochron-burial dating of strath terraces, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1787, https://doi.org/10.5194/egusphere-egu26-1787, 2026.

In areas of multiple exposure-burial histories the use of two cosmogenic radionuclides (CRN) with different half-lives allows to reveal the disequilibrium between CRN concentrations and provide a better understanding of landscape evolution. This study aims to quantify bedrock denudation rates in the Western Mecsek Mts (southern Pannonian Basin), a low-elevation hilly area that is currently being exhumed from under its loess cover deposited during the Quaternary glaciations. Concentrations of ¹⁰Be and ²⁶Al were measured in samples taken from flat, soil-covered ridge tops and stream sediments from several small river catchments composed of Permian and Triassic sandstones and conglomerates. Low ²⁶Al/¹⁰Be ratios are indicative of unsteadiness caused by significant past burial of the bedrock surfaces. A Monte Carlo (MC) model was developed to reveal the temporal evolution of the loess cover as a function of glacial-interglacial climate, and to determine the true rate of bedrock denudation accounting for both loess-covered periods with shielding and zero erosion as well as phases of exposure and bedrock denudation during periods without loess.

Our model showed that higher-elevation catchments and ridges were exposed for 40 to 85%, while lower-elevation areas were uncovered for less than 30% of time during the last 1 Ma. The modelled time integrated bedrock denudation rates were similar for the ridge crests and basin-averaged samples suggesting a steady relief. However, a well-expressed difference was found between the areas spending most of the time loess covered and the less covered group with mean integrated denudation rates of 5±5 m/Ma and 19±8 m/Ma, respectively. Single nuclide ¹⁰Be denudation rates overestimated the modelled, time-integrated denudation rates by a factor of ~1.5 for the more exposed group and by a factor of ~13 (up to >30) for the mostly covered areas. These rates, especially the latter, are slower than published values for similar climatic, tectonic, and topographic settings. If the simple, single nuclide ¹⁰Be approach was used, these differences would have remained hidden, and the true lowering rate of bedrock would have been overestimated by a factor that increases with the shielding time.

This is the first study quantifying the influence of past loess covers on CRN concentrations in bedrock and to estimate the denudation rates corrected for this shielding. Our findings reveal that the steady-state assumption of the CRN concentrations may also be violated in small, non-glaciated catchments without intermittent sediment storage. Where single-nuclide ¹⁰Be denudation rates are higher than sediment-trap estimates, the shielding effect of past sediment cover (such as loess) could also explain the discrepancy. Accordingly, we recommend the use of the paired ²⁶Al/¹⁰Be approach to test the presumption of cosmogenic nuclide equilibrium not only in large catchments and formerly glaciated areas, but also in settings where past sediment cover may have lasted long enough to lower the CRN ratio.

Funding: PURAM, Mecsekérc Ltd., NKFIH project FK 124807. Sample processing: Cosmogenic Laboratories of Budapest (n=16) and of the University of Edinburgh (n=4); AMS measurements: ASTER, Aix en Provence (n=16) and SUERC, Glasgow (n=4)

How to cite: Ruszkiczay-Rüdiger, Z., Knudsen, M. F., Bauer, M., Telbisz, T., Team, A., and Sebe, K.: Quantification of Quaternary loess cover and integrated denudation rates using cosmogenic nuclide Aluminium-26 and Beryllium-10 disequilibrium (Mecsek Mountains, Pannonian Basin), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2959, https://doi.org/10.5194/egusphere-egu26-2959, 2026.

Over the past decade, several research groups have developed and applied methods for using Infra-Red Stimulated Luminescence (IRSL) from sand-sized grains of alkali feldspar collected from the active channels of different rivers. These methods used either conventional multiple grain IRSL measurements, or single grain IRSL determinations, but all depend on comparisons of results from different sampling locations to reconstruct virtual velocity. In its simplest form, this approach relies on the Ergodic principle as the basis for time-space equivalence of different samples. While this can often represent a successful approach, recent anthropogenic disturbances to fluvial systems may in some cases render this method problematic. For example, where channel engineering or dam construction cuts off or modifies the natural sediment supply, samples collected downstream of these locations may provide signals that are inconsistent with those from upstream.

For this reason, our research team has been developing IRSL approaches to attempt to reconstruct sediment storage times and virtual velocity by inverting measured Multiple Elevated Temperature (MET) IRSL signals from single grains of alkali feldspar. Some grains preserve a record that is shaped by multiple episodes of storage during burial and light exposure during transport; storage causes trapped charge populations responsible for IRSL signals to grow in a predictable manner, while light exposure causes a reduction in each population. Multiple IRSL signals measured at a range of temperatures in the laboratory display different sensitivity to light, resulting in different degrees of “bleaching” (reduction in trapped charge). When a grain is subject to multiple episodes of burial and bleaching, the different IRSL signals move away from being in an equilibrium ratio with each other, allowing us to constrain their past burial and bleaching histories, within some limits. In this presentation, we shall compare results from this novel single grain MET-IRSL inversion approach with conventional IRSL sediment transport approaches, and assess performance from grains subject to laboratory simulations of different burial-bleach cycles. The new technique has great potential to help understand contemporary and past fluvial dynamics and sediment storage, as well as determination of sediment sources and channel erosional processes, and can contribute significantly to applications such as catchment carbon dynamics, or assessing impacts of engineering structures.

How to cite: Rhodes, E. and Spano, T.: Reconstructing virtual velocity and fluvial dynamics using MET-IRSL from single grains of sand, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4552, https://doi.org/10.5194/egusphere-egu26-4552, 2026.

Luminescence ages are powerful agents for tracing past sediment dynamics and deciphering complexities inherent in the evolution of past landscapes. If applied in temporal periods suitable for luminescence-based methods, they provide accurate dating results but with somewhat limited spatial resolution. This is primarily due to the time-consuming nature of luminescence sample preparation and measurement procedures. Luminescence screening methods, for instance, using portable equipment [1] that focuses only on light intensities rather than absorbed dose/dose-rate ratios, provide a convenient shortcut. Assuming a suitable geologically homogeneous environment, they provide initial insights and relative chronologies and can be useful in developing an appropriate sampling strategy for a more detailed study.

However, the hope of delivering, even provisionally, instant chronologies could not yet be satisfied. While our approach similarly cannot offer instant chronologies, we propose here a gradient-boosted decision tree approach [2] to model the complex interactions among physical parameters (e.g., dose rate, water content, sedimentology) and convert luminescence intensity values into the age domain. Our approach uses age-depth relationships of ages and intensities from different profiles, combined with additional features such as geographical information (latitude, longitude, depth below ground surface). We demonstrate that we can satisfactorily and robustly predict pseudo-luminescence ages from signal intensities using only a small training dataset (n = 31). This enables us to considerably enhance the age resolution of luminescence dating chronologies in suitable environments, particularly in those where sedimentary deposits are relatively homogenous.

A limitation of our approach is our reliance on a favourable, homogeneous sampling environment (here, sandy deposits of aeolian origin), which cannot be directly transferred to other geologically more complex settings; however, we are confident that the general approach remains valid and can be adapted on regional scales to increase age resolution.

References

[1] Sanderson, D. C. W. and Murphy, S.: Using simple portable OSL measurements and laboratory characterisation to help understand complex and heterogeneous sediment sequences for luminescence dating, Quaternary Geochronology, 5, 299–305, https://doi.org/10.1016/j.quageo.2009.02.001, 2010.

[2] Chen, T. and Guestrin, C.: XGBoost: A Scalable Tree Boosting System, in: Proceedings of the 22nd ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, New York, NY, USA, 785–794, https://doi.org/10.1145/2939672.2939785, 2016.

How to cite: Kreutzer, S., Heydari, M., Hanson, P. R., Kadereit, A., Mahan, S. A., and Schmidt, C.: A gradient boosted decision tree approach for high-resolution luminescence chronologies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5323, https://doi.org/10.5194/egusphere-egu26-5323, 2026.

The Thermochronology @ Purdue (T@P) noble gas mass spectrometry facility was established at Purdue University between 2020 and 2023. In this presentation, we will detail the T@P laboratory’s instrument configuration and demonstrate the facility’s capabilities for both helium-based thermochronometry and cosmogenic noble gas geochemistry. The primary instrument in the T@P laboratory is an Isotopx NGX, a multi-collector sector field mass spectrometer with a Nier-type source, which has a custom detector configuration consisting of three discrete dynode electron multipliers, including one fitted with an electrostatic filter, and two Faraday cups with ATONA® amplifiers. The NGX is connected to a custom-built, fully automated, ultra-high vacuum extraction line that includes an activated charcoal cryogenic trap and two getters for gas purification, two manometrically-calibrated gas standards for sensitivity calibration (air and ³He-enriched helium), and a manometrically-calibrated ³He spike for measurements of radiogenic ⁴He by isotope dilution. Gases are extracted by heating samples under vacuum using a diode laser system in a feedback control loop with either a calibrated optical pyrometer (better than ± 10 ºC precision), or a bare, thin-wire thermocouple in contact with the sample (better than ± 3 ºC precision). We will present isotopic analyses made in the T@P laboratory of reference materials for both helium-based thermochronometry (Durango apatite) and cosmogenic noble gas geochemistry (CRONUS-P, CRONUS-A, CREU-1) as well as from example applications in Earth and planetary surface processes.

How to cite: Tremblay, M. M., Guo, H., Dziekonski, E. T., Ickert, R. B., and Blair, D.: Helium-based thermochronometry and cosmogenic noble gas geochemistry in the Thermochronology @ Purdue (T@P) noble gas mass spectrometry facility, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5827, https://doi.org/10.5194/egusphere-egu26-5827, 2026.

Sufficient temperature rise during frictional heating is a key parameter controlling whether luminescence dating of fault gouges can determine the timing of past earthquakes. Regardless, the true temperatures induced in the rock during a co-seismic slip event are often unknown. This significantly hampers the accuracy of luminescence age results from fault gouges. Laboratory-controlled friction experiments can adequately simulate different friction scenarios by modulating normal stress and slip velocity and then recording induced temperatures using thermocouples [1] or an infrared camera [2]. However, monitoring those events in nature is highly impractical for past events.

Systematic luminescence studies on ultraviolet (UV) radiofluorescence (RF) of quartz reported a strong correlation between heating and subsequently recorded UV-RF signaldynamics [3,4].

Here, we explore the potential of UV-RF to shed light on the extent of friction-induced temperature in quartz-bearing host rocks. In our experiments, we tested one sediment quartz sample with a known luminescence characteristic and a polymineral sample from the North Tehran Fault. For one part of each sample, we first recorded a UV-RF temperature profile after heating subsamples in batches from 30 ºC to 575 ºC in increments of 25 ºC. The other (untreated) part was then subjected to frictional heating in the laboratory under a normal stress of 12 MPa and a slip velocity of 5 cm/s using a rotary shear apparatus. During the experiment, the frictional heat was recorded using an infrared camera. We then measured the UV-RF signal and projected the results onto the signal-preheat profile to estimate the (unknown) frictional heat temperature.

Although our study is preliminary at this stage, we could calculate realistic friction-induced temperatures for the quartz sample. In contrast, the UV-RF signals of the polymineral sample will require additional experiments. We will present the experimental design and initial results, and discuss the challenges and the potential of our approach for tracking the temperature levels generated by earthquakes.

References

[1] Kim, J.H., Ree, J.-H., Choi, J.-H., Chauhan, N., Hirose, T., Kitamura, M., 2019. Experimental investigations on dating the last earthquake event using OSL signals of quartz from fault gouges. Tectonophysics 769, 228191. https://doi.org/10.1016/j.tecto.2019.228191

[2] Heydari, M., Kreutzer. S., Hung, C.C., Martin, L., Ghassemi, M.R., Tsukamoto, S., Niemeijer, A., under review, Scientific Reports. Unveiling Earthquakes: Thermoluminescence Signal Resetting of a Natural Polymineral Sample in Laboratory-Produced Fault Gouge

[3] Friedrich, J., Pagonis, V., Chen, R., Kreutzer, S., and Schmidt, C.: Quartz radiofluorescence: a modelling approach, Journal of Luminescence, 186, 318–325, https://doi.org/10.1016/j.jlumin.2017.02.039, 2017a.

[4] Friedrich, J., Fasoli, M., Kreutzer, S., and Schmidt, C.: The basic principles of quartz radiofluorescence dynamics in the UV - analytical, numerical and experimental results, Journal of Luminescence, 192, 940–948, https://doi.org/10.1016/j.jlumin.2017.08.012, 2017b.

How to cite: Heydari, M., Niemeijer, A., and Kreutzer, S.:  Radiofluorescence as a tool to estimate the degree of friction-induced heat caused by co-seismic slip , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5853, https://doi.org/10.5194/egusphere-egu26-5853, 2026.

Constraining rock time–temperature histories below ~100 °C (corresponding to the upper ~3 km of the Earth’s crust) is crucial for understanding the interactions between tectonics, erosion, and climate over Quaternary timescales. However, reconstructing thermal histories spanning 10⁴-10⁶ years within the ~25-75 °C temperature range remains a significant challenge. Trapped-charge dating techniques, such as Optically Stimulated Luminescence (OSL) and Electron Spin Resonance (ESR), enable measurement of different temperature-sensitive (< 100 ^oC) trapped charge dating signals within quartz minerals, thereby offering the potential to fill this temporal and thermal gap. Quartz OSL signals often saturate over timescales of ~10⁴ years, while ESR signals saturate over longer timescales of ~10⁶ years; used together, these methods provide a powerful tool for constraining cooling and exhumation histories over the Quaternary.

A key challenge in establishing quartz OSL and ESR thermochronometry as a robust method lies in the lack of reliable and comprehensive benchmark studies. This study addresses this limitation by investigating quartz from drill-core sediments in the Anadarko Basin (Oklahoma, USA) with a well-constrained temperature history (~30−80 ^oC) based on empirical calibration with a stable geothermal gradient. Down-core measurement of OSL and ESR signals show promising results exhibiting a systematic decrease in intensity with increasing temperature (and depth), with OSL signals reaching saturation in the lower temperature range. Here, we conduct a detailed investigation of sample-specific signal saturation limits, thermal decay kinetics and temperature-sensitivity of OSL and ESR signals, followed by inversion of these different trapped charge signals for temperature. Our results provide a comprehensive and robust benchmark study to assess the potential and limitations of quartz OSL and ESR thermochronometry for reconstructing temperature histories in natural settings.

How to cite: Dave, A. K., Kranz-Bartz, M., Jepson, G., Bernard, M., Schmidt, C., Margirier, A., and King, G. E.: Quartz luminescence and ESR thermochronometry of drill-core sediments from the Anadarko Basin, USA, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8126, https://doi.org/10.5194/egusphere-egu26-8126, 2026.

During the Quaternary period the Fennoscandian ice sheet reached far into Europe on several occasions. Especially the last two ice sheet expansions, the Saalian and Weichselian, left many marks on the Danish land surface and shaped the landscape, leaving behind outwash plains, terminal moraines, tunnel valleys, and other glacial landforms. Although, there is general consensus regarding which ice advances resulted in which landscape features, most correlations have not yet been verified by absolute dating. To improve constraints on the ice cover history of the Danish area, we have carried out ¹⁰Be profiling on several outwash plains across Denmark. These outwash plains have been chosen (i) to constrain the timing of the overall ice margin retreat across Denmark, and (ii) to decipher whether the northern part of the prominent 90-degree landform (the “Main Stationary line”) belongs to the Last Glacial Maximum advance (~20.000 years ago) or a previous ice advance, such as the Kattegat advance (~30.000 years ago). Denmark is located right at the foothills of the Fennoscandian ice sheet, and we expect our results to have strong implications on the understanding of ice sheet dynamics at play during advance-retreat cycles of continental sized ice sheets, as well as to improve the understanding of the glacial history of Northern Europe. At EGU some of the preliminary results from this investigation will be presented.

¹⁰Be profiling is a technique which involves sampling sediment from several depths below the surface at a specific location. Interpretation of the ¹⁰Be concentrations can lead to age estimation of the sampled deposit, since the concentrations will depend on the cosmogenic exposure history of the sediment package. A set of samples from different depths are needed to separate the pre- and post-burial ¹⁰Be nuclide concentrations or to draw attention to ¹⁰Be irregularities throughout the profile indicating asynchronous deposition. The numerical modelling of nuclide concentrations carried out in this study serves as proof of concept and highlights the applicability of the ¹⁰Be profiling approach. Hence, alongside the preliminary results of the study, our novel MATLAB implementations for interpreting ¹⁰Be profiles will also be showcased.

How to cite: Allaart, L., Nørgaard, J., Knudsen, M. F., Andersen, L. T., Nielsen, J. B., and Larsen, N. K.: Dating DK: Cosmogenic 10Be depth profiling of glacial outwash plains in Denmark, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9469, https://doi.org/10.5194/egusphere-egu26-9469, 2026.

Basin-averaged erosion rates derived from cosmogenic nuclide concentrations are one of the most commonly used data for the study of landscape evolution histories across a wide range of tectonic and climatic regimes. Despite recent advances in global nuclide datasets and analytical techniques, methods for converting measured concentrations into denudation rates have progressed little.

Converting cosmogenic nuclide concentrations to denudation rates requires several key assumptions; however, one in particular is more difficult to assess, which is that denudation rates remain spatially and temporally constant over timescales comparable to the nuclide integration period. These assumptions rarely hold in nature, especially in mountain catchments with pronounced knickpoints propagating upstream, complicating the interpretation of a single mean concentration. Previous studies have often only evaluated how mean concentrations are affected when one or more assumptions are violated. However, minerals sampled from complex landscapes likely represent distinctly non-Gaussian populations that cannot be adequately characterized by a single mean value.

We present modelling results of cosmogenic nuclide concentration distributions in catchments experiencing spatially and temporally variable denudation rates under different tectonic and climatic forcings. Analysing concentration distributions rather than mean values alone reveals how assumption violations affect inferred denudation rates. Our model employs a detachment-limited stream power law and calculates nuclide accumulation from multiple production pathways using the Lifton-Sato-Dunai scaling scheme.

Preliminary results indicate that the presence of knickpoints does not significantly compromise the interpretation of cosmogenic nuclide concentrations except in cases with fast knickpoint retreat rates in high-relief catchments. However, we find that even moderate climatic changes (simulated by varying the erodibility constant), can yield significant errors in inferred versus real denudation rates. We propose that simple evaluations of cosmogenic nuclide distributions can enhance the reliability of denudation rate estimates in future applications.

How to cite: Grimm, L., Adams, B. A., and Fox, M.: Understanding key assumptions in cosmogenic nuclide-derived catchment-average denudation rates, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12912, https://doi.org/10.5194/egusphere-egu26-12912, 2026.

The timing and drivers of canyon incision across the Colorado Plateau are strongly debated, particularly the roles of deep-seated processes, tectonics, geological inheritance, and climate. A major limitation in resolving canyon incision histories and their controlling processes is that the amount of exhumation associated with incision is often too small to be robustly recorded by classical low-temperature thermochronometers such as apatite fission track and (U–Th)/He. Resolving the timing of exhumation acceleration and onset of canyon incision therefore requires thermochronological tools sensitive to lower temperatures and shorter timescales, such as electron spin resonance (ESR).

Here, we focus on Zion Canyon, an emblematic and well-studied canyon on the western margin of the Colorado Plateau, to evaluate the potential of ESR thermochronology to resolve late Cenozoic to Quaternary exhumation/incision histories. Classical low-temperature thermochronometers suggest that exhumation began around 7 Ma. This exhumation signal integrates regional plateau denudation and canyon incision, preventing the isolation of incision-specific dynamics. In contrast, independent geomorphic constraints document significantly higher incision rates over the last ~1 Myr, implying temporal variations in incision that cannot be resolved with classical thermochronology.

We apply ESR thermochronology to a bedrock elevation profile from Zion Canyon to (i) quantify Quaternary incision rates and (ii) test for changes in cooling rates associated with canyon incision. Preliminary ESR results reveal an increase in cooling rates at ~3–2 Ma, suggesting an acceleration of incision during the late Pliocene–early Pleistocene. These results highlight the potential of ESR thermochronology to bridge the temporal gap between geomorphological constraints and classical thermochronology, and to provide new quantitative constraints on the timing and rates of canyon incision across the Colorado Plateau. In addition, preliminary data from the Grand Canyon (where the incision history is particularly complex and controversial) suggest that ESR signals are not saturated, highlighting the method’s potential to resolve cooling and exhumation over the last few million years in other canyons.

How to cite: Margirier, A., Dave, A. K., Jepson, G., Thomson, S., Valla, P. G., Voigtländer, A., Schmidt, C., and King, G. E.: Bridging classical low-temperature thermochronology and geomorphology: ESR thermochronology constraints on Plio-Quaternary exhumation and canyon incision across the Colorado Plateau, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12968, https://doi.org/10.5194/egusphere-egu26-12968, 2026.

The scarcity of terrestrial temperature proxies has been a major challenge in the reconstruction of continental climate evolution throughout the Last Glacial Maximum (LGM) and the Pleistocene-Holocene transition. Understanding such extreme climatic conditions and major system shifts in Earth’s history is paramount for constraining climate sensitivity and predicting future climate evolution in the light of rising greenhouse gas concentrations.

Our research aims to develop a globally applicable method for temperature sensing during this timescale using the low-temperature (i.e., 200–280 °C) thermoluminescence (TL) signal of near-surface bedrock feldspar which has been demonstrated to be sensitive to terrestrial surface air temperature fluctuations over geological timescales (Biswas et al., 2020). As such, palaeothermometry represents one of few available proxies for terrestrial temperature and can aid in quantifying the magnitude of rapid climate changes on a more local scale.

While the theoretical feasibility of TL palaeothermometry has been demonstrated (Biswas et al., 2020), it still requires accurate validation on additional samples of well-constrained temperature history. Furthermore, the method has not yet been applied to a broad set of samples for temperature reconstruction purposes.

Our contribution aims to close this knowledge gap by benchmarking recent methodological improvements against samples from borehole sites located in Germany and Japan. We further present first surface air temperature reconstructions at a number of study sites, which we intend to use to constrain the evolution of altitudinal and latitudinal temperature gradients since the LGM. We show that TL palaeothermometry can be used to retrieve accurate rock and surface air temperatures and may now be more routinely applied.

References

Biswas, R.H., Herman, F., King, G.E., Lehmann, B., Singhvi, A.K., 2020. Surface paleothermometry using low-temperature thermoluminescence of feldspar. Clim. Past 16, 2075-2093.

How to cite: Oehler, S., Niyonzima, P., King, G. E., Biswas, R. H., Herman, F., Bernard, M., Margirier, A., Nalwanga, R., El-Raei, M., and Schmidt, C.: Development of a globally applicable palaeothermometry method based on luminescence: Advances in method development and validation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13563, https://doi.org/10.5194/egusphere-egu26-13563, 2026.

Rock glaciers are common permafrost features in mountain landscapes around the globe with a geohazard relevance sourcing large amounts of debris while also acting as aquifers storing large amounts of water, yet their long-term (i.e. centennial to millennial scale) dynamics remain poorly constrained due to limited dating efforts. Short term observations, via GPS, InSAR, UAVSAR, Lidar or feature tracking, show acceleration of flow rates of rock glaciers in all mountain regions.

We use rock glacier RG-2 in the Uinta Mountains (Utah, USA, 3 300 m asl) as a natural laboratory to test and cross-calibrate a novel luminescence-based surface dating technique: optically stimulated luminescence rock surface exposure dating (OSL RSeD). This method exploits the latent OSL or IRSL signals stored in quartz and feldspar bearing rocks and the fact that, in the upper centimeters of rock surfaces, these signals are reset (zeroed) by daylight exposure. By integrating previously CRN-dated quartzite boulders (n = 9) on RG-2 into our analysis, we (i) assess the sensitivity of parameters in the OSL bleaching-with-depth model, (ii) evaluate the model’s underlying assumptions, and (iii) interpret the resulting OSL ages.

Furthermore, we present a standardized, statistically robust workflow to normalize luminescence-depth profiles to saturation based on sequential analysis, suitable for datasets obtained by the 1D-coring-and-slicing- as well as the 2D-EMCCD-approach for various geological and archaeological dating applications.

How to cite: Sperlich, D., Munroe, J., Ramisch, A., and Meyer, M. C.: Cross-Calibration and Sensitivity Analysis of OSL Rock Surface Exposure Dating Using Cosmogenic Nuclide Ages on an Uinta Mountains Rock Glacier (Utah, USA), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14245, https://doi.org/10.5194/egusphere-egu26-14245, 2026.

Over the past few centuries, the natural flow of river water and sediment has been significantly disrupted by human activities, including land‐use change, dam and reservoir construction, and variable precipitation. Sediment accumulation in reservoirs leads to declining storage capacity, reduced water quality, and navigational challenges. While hydraulic models can characterize these issues over annual to decadal timescales, they are less effective for predicting sedimentation trajectories over decades to centuries. At these longer timescales, feedbacks between reservoir sedimentation and upstream erosion and deposition influence delta growth and sediment delivery, complicating the development of long-term sediment management strategies. To address this gap, we developed a workflow for building and calibrating open source, coupled landscape evolution models (LEMs) and delta sedimentation models (DSMs) for real-world watersheds. Here, we present preliminary results from the Chattahoochee River in the southeastern United States. The river is segmented by six major dams, each creating a reservoir and corresponding sub-catchment. We constructed a set of six LEMs using Landlab (one for each sub-catchment) and run them sequentially from upstream to downstream, using the sediment outflux from each model as input for the next. The LEMs are calibrated using cosmogenic ¹⁰Be mean catchment erosion rates, modern land-use data, and sediment trapping calculations. We then evaluated how well each model reproduced watershed sediment fluxes inferred from late 21st century suspended-sediment measurements. The DSMs are constructed using PyDeltaRCM and are driven by output sediment flux and provenance data from the LEMs. Using the pre-reservoir topography as a boundary condition, we validate the models by replicating the post-reservoir delta growth. We then use variable land use and hydraulic forcings in the LEMs to assess different future sedimentation patterns in the deltas. Our workflow can be easily applied to any reservoir with bathymetric data and can help stakeholders understand how upstream human impacts may influence a range of possible sedimentation patterns over the coming decades.

How to cite: Sheehan, C., Behn, M., Snyder, N., Cortese, L., and Dahl, T.: From Free-Flowing to Fragmented: Using Calibrated Models to Assess Impacts of Multiple Dams on Watershed Evolution, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14441, https://doi.org/10.5194/egusphere-egu26-14441, 2026.

The rate of bedrock river incision both regulates and depends on the size distribution of sediment produced on hillslopes. Quantifying how hillslope sediment size varies across catchment scales is therefore fundamental to understanding feedbacks between weathering, erosion, and tectonic uplift in mountain landscapes. Here, we quantify spatial variations in hillslope sediment size distributions within a steep mountain catchment using a numerical model that combines a granulometric analysis of detrital cosmogenic nuclide and apatite (U–Th)/He age measurements from each of twelve sediment size classes ranging from medium sand to boulders. The model accounts for sediment production, mixing, and particle size evolution during transport using particle-wear relationships calibrated from tumbling experiments conducted in rotating wheels of varying size. Because these experiments span five orders of magnitude in calculated sediment energy, they enable upscaling of measured abrasion and fragmentation relationships from laboratory to field conditions. 

Measured age distributions by size class show excesses and deficits relative to spatially uniform erosion that we detect using a Monte Carlo-based departure analysis. For example, cobbles at the outlet are relatively old and thus preferentially derived from higher elevations while boulders are relatively young and thus preferentially derived from lower elevations. When these granulometric elevation distributions are combined with measured granulometric variations in cosmogenic nuclides, our model predictions are consistent with independent field-based measurements of hillslope sediment size distributions and their spatial variability across the catchment. Hence, the measured size-dependent variations in cosmogenic nuclides at our study site need not be attributed solely to depth-dependent shielding of relatively coarse material on steep hillslopes. Instead, the granulometric variability in isotopic tracers can be explained by the linkage between erosion rate and particle size production. Together, these results demonstrate that coupling granulometric cosmogenic nuclides and tracer thermochronology with empirically calibrated particle-wear relationships provides a powerful framework for predicting spatial variations in sediment production and erosion in mountain landscapes.

How to cite: Riebe, C., Sklar, L., and Lukens, C.: Hillslope sediment size distributions revealed by granulometric cosmogenic nuclides, detrital thermochronology, and experimentally calibrated particle wear relationships, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15046, https://doi.org/10.5194/egusphere-egu26-15046, 2026.

Erosion breaks down mountains, yet it is sediment transport that removes sediment and transforms landscapes. Quantifying the rates of sediment transport is a challenging task. Luminescence, traditionally a Quaternary dating method, offers a means to help us constrain sediment transport as a unique sunlight-sensitive tracer. One of the sediment transport properties that luminescence can potentially constrain is the characteristic transport lengthscale, or hop length, that describes the mean distance of transport between long-term storage events, or rest times. Here, I discuss considerations for using luminescence to estimate hop lengths and rest times with potentially heavy- and thin- tailed probability distributions. I present recent work modeling transport distance versus in-channel sunlight exposure and highlight recent contributions in the literature that show the impressive potential of luminescence sediment tracing.

How to cite: Gray, H.: Estimating sediment transport scales with luminescence as a sediment tracer, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15487, https://doi.org/10.5194/egusphere-egu26-15487, 2026.

Located at an active arc-continent collision zone subject to a tropical climate, the Taiwan mountain belt is characterized by intense tectonic activity, resulting in rapid landscape evolution. In the Western Foothills of southwestern Taiwan, geodetic data reveal rapid surface deformation during periods of low seismicity, where the upper crust is dominated by mudstone lithology. However, mapped active structures do not fully explain the observed sharp deformation gradients and uplift patterns. This discrepancy motivates an evaluation of how strain is accommodated across different timescales and whether the present-day deformation reflects persistent long-term kinematics or transient processes.

Using the ratio of meteoric ¹⁰Be to mineral-weathered ⁹Be measured from five river-sediment samples collected from watersheds with distinct short-term uplift rates, spatial variations in basin-scale denudation rates (D_met) and their relationship to short-term uplift are evaluated. Although meteoric-¹⁰Be-derived denudation rates are particularly suitable for quartz-poor regions such as southwest Taiwan, the method relies on several assumptions that require validation. To assess its applicability, additional samples were collected from watersheds in the Central Range east of the study area, where in situ ¹⁰Be-derived denudation rates (D_insitu) are available.

In the Western Foothills area, D_met successfully captures large-basin denudation (0.77 ± 0.07 mm/yr) as the integrated signal of sub-basin denudation rates (average of 0.74 ± 0.01 mm/yr). Across two regions, D_met values are systematically lower in the Western Foothills than in the Central Range (5.8 - 7.4 mm/yr, with an outlier of 32 mm/yr), reflecting contrasts in lithology, climate setting, and topographic relief. In the Central Range, D_insituvalues (0.2-4.5 mm/yr) differ from D_met, suggesting that potential grain-size differences between the two methods lead to distinct sediment transport behaviors. Nevertheless, D_met remains informative by reproducing basin–sub-basin integration in the Western Foothills and distinguishing denudation regimes between regions.

Within the Western foothills, D_met correlates weakly with uplift rate, slope, and relief. The normalized channel steepness index (k_sn­) shows an unexpectedly weak to negative relationship with D_met. This pattern suggests that meteoric ¹⁰Be-derived denudation rates might not represent short-term surface deformation rates or are integrated over timescales that differ from those represented by geomorphic indices. This likely reflects transient surface adjustments rather than steady-state conditions. In contrast, D_met seems to positively correlate with the extent of barren-land (badland) surfaces developed in weak mudstone formation, suggesting first-order control on basin-averaged meteoric ¹⁰Be inventories. Although badlands have been proposed to be associated with rapid erosion in this region, the correspondence between their development timescale and the integration timescale of meteoric ¹⁰Be derived denudation remains uncertain.

Future work will expand sampling across additional basins spanning a wider range of badland extent and uplift signatures to test the robustness of these relationships and refine the link between short-term deformation and longer-term surface response. Additional analyses will quantify meteoric ¹⁰Be inventories on barren land and vegetated hillslopes to evaluate differences in meteoric ¹⁰Be retention across contrasting hillslope environments, thereby refining the applicability and sensitivity of the methods to hillslope transport processes.

How to cite: Nguyen, N.-T., Siame, L., Le Béon, M., Léanni, L., Pathier, E., and Team, A.: Landscape Response to Rapid Uplift in Southwestern Taiwan: Insights from Denudation Rates Measurement from Cosmogenic 10Be (Meteoric)/9Be Ratios and Morphometric Indices, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15516, https://doi.org/10.5194/egusphere-egu26-15516, 2026.

High-definition digital elevation models (DEMs) from airborne light detection and ranging (LiDAR) are very powerful tools in detecting unknown tectonic-geomorphic features and quantifying cumulative slip from repeated faulting events. The faulted geomorphic features, however, need to be somehow dated to convert the slip to long-term slip rate, and this task still remains as a challenging part of many tectonic geomorphic and paleoseismic studies. The dating is particularly difficult in mountainous and densely vegetated regions, where we are most benefitted from LiDAR DEMs but most often confront challenges in finding datable organic materials in high-energy gravelly deposits. Here we attempted to date left-laterally faulted fluvial terrace surfaces discovered along the Nobi active fault system (NAFS) in the Etsumi Mountains, central Japan, by using a terrestrial cosmogenic nuclide Be-10. In this region, terrace surfaces are covered with thin aeolian loess deposits of <1 m thick, with generally thinner loess cover on younger and lower surfaces. We employed the depth-profile method to simultaneously determine the age and inherited nuclide concentration, incorporating the effect of loess deposition after terrace abandonment. Exploratory pits for depth profiling were excavated at two sites along the NAFS; the Nukumi-Shiratani site on the low terrace surface along the Nukumi fault and the Nogo site on the middle terrace surface along the Neodani fault. Our results show the terrace abandonment ages that are consistent with the generally accepted terrace-formation and incision history modulated by global climate changes (MIS 2 and MIS 4 for the low and middle terrace surfaces, respectively) and also with crypto tephras identified in the loess deposits. In turn, the long-term left-lateral slip rate for the Nukumi fault was first determined whereas that for the Neodani fault proved to be substantially larger than estimates from previous studies.

How to cite: Kaneda, H., Matsushi, Y., Ogura, Y., Ohta, R., and Matsuzaki, H.: Dating faulted terrace surfaces with thin aeolian loess cover by using terrestrial Be-10 depth profiles: an attempt along the Nobi active fault system, central Japan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16139, https://doi.org/10.5194/egusphere-egu26-16139, 2026.

The observation that topography trends with snowline altitude despite large differences in tectonic uplift in various locations provides the foundation of the glacial buzz-saw hypothesis. However, despite numerous modelling studies, very few quantitative data are available that document the timing or rate of glacial topography formation. Consequently, challenges remain to explain why some localities (e.g. Alaska, southern Andes) seem to escape the glacial buzz-saw. This data gap is driven by the difficulty in constraining rates of glacial erosion over kyr-Myr timescales.

Here, we use a novel thermochronometry technique, based on the Electron Spin Resonance (ESR) of quartz minerals, to constrain the timing of cirque basin formation adjacent to the Rhône valley, Switzerland. The Fully basin, near the town of Sion, sits above the ~1.5 km deep glacial Rhône valley, and is thought to have been incised by ~400 m during the Quaternary. Samples were collected in a transect across the basin, and complement samples previously investigated using ESR-thermochronometry from the Rhône valley (Wen et al., 2024).

Forward modelling using a modified version of Pecube together with the kinetic parameters of existing ESR samples from the area (Wen et al., 2024) shows that ESR-thermochronometry data should be able to constrain the timing of cirque basin incision. This will provide the first dates and rates of glacial buzz-saw activity and will be contrasted with the timing of Rhône valley incision.

How to cite: King, G., Bernard, M., Wen, X., Cox, S., Dave, A., and Schmidt, C.: Putting rates on the buzz-saw? Constraining the timing and rate of cirque valley incision, Rhône valley, Switzerland., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16746, https://doi.org/10.5194/egusphere-egu26-16746, 2026.

Past glacier fluctuations can be reconstructed successfully via cosmogenic nuclide exposure dating of boulders protruding from the moraine surface. However, post-depositional processes like denudation, slope failure and weathering, together with nuclide inheritance, potentially affect nuclide concentrations and diminish the accuracy of moraine age estimates. Post-depositional exhumation of boulders leads to incomplete cosmic-ray exposure and thus underestimated ages. Conversely, some boulders contain nuclides produced prior to their deposition (nuclide inheritance) due to insufficient depth of glacier erosion, incorporation of older glacigenic sediments or material from surrounding non-glaciated areas. Nuclide inheritance yields age estimates older than the true age of moraine formation.

With an aim to evaluate the controls on moraine denudation and to gain insights to the reliability of exposure dating and sampling strategy, we compiled a global dataset of 10,083 ¹⁰Be-based exposure dates from the Expage database. Clustering of exposure ages from each moraine was used as an indicator of dating quality, assuming that boulders without prior or incomplete exposure should yield a well-clustered (MSWD<2) age. Moraine age-clustering was analysed with respect to climate, topography, location and type of ice mass. 

We find that just 23% of moraine ridges with at least three exposure dates show well-clustered exposure ages, increasing to 69% after iterative removal of outliers with the highest deviation. Exposure-age clustering is mainly a function of moraine age: clustering is best among moraines of 15–10 ka age and decreases notably for moraines that are either younger or older. Climate also matters: well-clustered moraine ages are more frequent in regions with milder climates experiencing higher mean annual temperature and precipitation and lower annual temperature range. Conversely, poorly-clustered ages (e.g. Antarctic Ice Sheet, Cordilleran Ice Sheet, northeastern Asia, High Mountain Asia and Greenland) appear to reflect aridity, extreme cold, or large annual temperature range, but may also stem from complex glacial histories involving multiple glacier readvances.

A key implication for moraine boulder sampling strategies is the effect of the number of samples per moraine. While 36% of the examined moraines comprise only three samples, the likelihood of obtaining a well-clustered age increases significantly by sampling four. The optimal number of samples varies with moraine age and climate. For moraines dated to 20–10 ka, four samples are generally sufficient, whereas younger or older moraines typically require seven or more samples to achieve a similar level of accuracy. The optimal number of samples increases toward colder climates, from temperate (3–4 samples or more) through boreal (5–6 samples or more) to polar climates (7 or more).

How to cite: Jandová, A., Stoker, B. J., Margold, M., and Jansen, J. D.: Controls on moraine exposure-age clustering and implications for sampling strategy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18749, https://doi.org/10.5194/egusphere-egu26-18749, 2026.

The southern Central Andes forearc preserves extensive low-relief wave-cut platforms and fluvial terraces that record long-term margin uplift, yet the timing and driving mechanisms are still debated. Here we present eleven new in situ ¹⁰Be exposure ages from high fluvial terraces and four ages from a lower terrace, combined with geomorphic analyses across eight adjacent catchments, to reassess the age and tectonic significance of the degradational surfaces (pediplain) present between 29.5 and 32.5°S. Erosion-corrected exposure ages indicate that the high terrace formed during the Early Pleistocene, while a lower terrace records incision at Middle Pleistocene. Longitudinal terrace–channel profiles reveal systematically increasing relief toward the coast that terminates near the surface projection of the 50–60 km slab-depth contour, coincident with the downdip limit of megathrust domain-C earthquakes. This spatial relationship supports a regionally coherent uplift signal produced by the cumulative effect of deep coseismic deformation. In peninsular settings, notably the Altos de Talinay, this long-wavelength signal is overprinted by short-wavelength uplift consistent with localized underplating. Our results demonstrate that the high fluvial terraces and the shore wave-cut platform constitute a single, regionally continuous geomorphic marker recording an Early Pleistocene forearc uplift phase extending from ~16° to 42°S. This orogen-scale emergence implies a subtle but widespread change in subduction dynamics during the last Early Pleistocene, the causes of which are not clearly understood.

How to cite: Gianni, C. R., Ballato, P., Schildgen, T., Gianni, G., Wittmann, H., Melnick, D., and Faccenna, C.: Geomorphic imprint of an Early Pleistocene uplift phase of the Andean forearc and its underlying mechanisms, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22489, https://doi.org/10.5194/egusphere-egu26-22489, 2026.

Luminescence dating of rock surfaces is an emerging and exciting branch of research in geochronology with great application potential. In principle the technique can be used to date hitherto undatable geological and archaeological materials or geomorphological landscape elements. As such, luminescence-based rock surface dating (RSD) is highly complementary to OSL sediment burial and other Quaternary dating techniques.   

RSD basically comes in two variants: rock surface burial dating (RSbD) and rock surface exposure dating (RSeD), both being highly active and promising geochronological research strands undergoing methodological development, refinement and testing. Meanwhile numerous ways of analyzing RSb and RSe luminescence data exist and different approaches to calculate rock surface ages have been introduced, yet no standardized way of handling RSb or RSe luminescence data has been put forward.

Here we present an open-source software package that is based on the software language Python©. The program enables users to evaluate their rock surface luminescence data via a simple graphical user interface (GUI). The program allows processing of data which originate either from CCD or EMCCD images or from the conventional "drilling and slicing" approach and takes various types of OSL, IRSL and IRPL signals into account. We incorporated all currently available and stat-of-the art bleaching models into the software package and provide the user with maximum degree of flexibility for normalizing luminescence signals. In the case of RSeD different calibration procedure options are implemented. Ultimately, the software allows single as well as multiple exposure and burial ages from rock surfaces to be derived.

How to cite: Meyer, M., Freiesleben, T., and Riedle, T.: The Python time machine – an open source software application for luminescence-based rock surface dating, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22933, https://doi.org/10.5194/egusphere-egu26-22933, 2026.

High-resolution 3D mapping of subterranean environments remains challenging due to their complex geometry, low-light conditions, and restricted accessibility. Among these environments, caves represent particularly demanding settings where detailed spatial documentation is essential for monitoring processes, supporting exploration and conservation efforts. Laser scanning has become a key technique for capturing accurate and detailed 3D representations of caves that form the basis for this heritage documentation and multidisciplinary research. Despite these advances, the creation of cave maps still commonly relies on traverse-line measurements and field sketches, later digitized using specialized cave-surveying software. In recent years, LiDAR data have been used for deriving the cave extent. While this method effectively captures the general geometry of cave passages, the delineation of cave-floor units, sediments, speleothems, rock blocks, and other features remains largely manual and relies heavily on the surveyor’s interpretation. As a result, feature boundaries vary between authors, and detailed cave-surface representation lacks reproducibility that is problematic for long-term documentation. In this study, we explore the use of deep-learning semantic segmentation for classifying selected cave-floor surface types based on geometric features derived from LiDAR data. Building on previous work focused on semi-automatic cave-map generation from LiDAR point clouds, we extend the workflow from deriving cave extent and floor morphology toward the automated interpretation of surface materials and forms. The method was tested on several common cave-floor surface types, including clastic sediments, flowstone, and bedrock, as well as artificial surfaces and objects typical in showcaves. The resulting classifications show that deep-learning models can distinguish surfaces with subtle geometric differences and produce consistent, reproducible delineations of units that are traditionally mapped by hand. Compared with manual digitization, the approach reduces subjectivity and provides a scalable way to generate polygonal layers used in speleocartographic workflows.

How to cite: Nováková, M., Šupinský, J., and Širotník, J.: Deep-learning classification of cave-floor surface types from LiDAR data for detailed cave mapping, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-807, https://doi.org/10.5194/egusphere-egu26-807, 2026.

Digital Elevation Models (DEMs) are fundamental to hydrological modelling, watershed delineation, flood hazard assessment, and resource management. However, the reliability of these applications depends heavily on the vertical accuracy of the DEMs. Although several global DEM products with 30-m spatial resolution are widely available, variations in sensor technology, data acquisition methods, and surface characteristics can significantly influence their accuracy and suitability for hydrological studies. This research provides a comparative evaluation of five commonly used global DEMs—TanDEM-X, ASTER GDEM, SRTM, Copernicus DEM, and ALOS World 3D—by assessing their vertical accuracy against high-resolution airborne LiDAR data and ICESat-2 ATL06 measurements. The findings aim to inform best practices for selecting DEMs in hydrological modelling and catchment-scale applications, particularly in data-scarce regions.

The Flinders River catchment in northern Queensland was selected as the critical test area for evaluating how DEM errors propagate into hydrological calculations. This region is characterised by low rainfall and pronounced topographic variability, encompassing flat lowland plains, dissected upland terrain, and localised areas of steep slopes. All DEMs were standardised to a common horizontal and vertical reference framework and co-registered with the test datasets to eliminate systematic discrepancies. ICESat-2 ATL06 data were rigorously filtered to retain only the highest-quality measurements, based on a combination of quality flags, topographic slope thresholds, and signal strength criteria in vegetated areas.

Elevation differences were computed at matched locations, and DEM performance was evaluated using key statistical metrics, including bias, root mean square error (RMSE), mean absolute error (MAE), median error, and standard deviation. To provide a more comprehensive assessment, error behaviour was analysed in relation to terrain slope and catchment characteristics, highlighting zones most vulnerable to error propagation in flow routing and watershed delineation. Systematic patterns in DEM error were further examined with respect to sensor characteristics under varying landscape conditions.

Results indicate that TanDEM-X and Copernicus DEM exhibit the highest vertical accuracy, closely aligning with ICESat-2 and LiDAR observations, whereas ASTER GDEM and SRTM show larger mean errors, particularly in dissected or mountainous terrain. These findings suggest that TanDEM-X and Copernicus DEM are preferable for hydrology-focused applications in semi-arid basins, while ASTER and SRTM should be used cautiously where precise modelling is required. The study underscores the importance of DEM accuracy evaluation in relation to basin characteristics, as errors can significantly influence hydrological modelling outcomes.

How to cite: Jafari, L., Jarihani, B., Koci, J., Sanislav, I., and Duce, S.: Comparative Analysis of 30-m DEM Products for Hydrological Applications: A Case Study in the Flinders Catchment Australia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1968, https://doi.org/10.5194/egusphere-egu26-1968, 2026.

Historical film-based images, acquired during aerial campaigns since the 1930s and from satellite platforms since the 1960s, provide a unique opportunity to document changes in the Earth’s surface over the 20th century. Yet, these data present significant and specific challenges, including complex distortions in the scanned image and poorly known exterior and/or interior camera orientation. In recent years, semi- or fully-automated approaches based on photogrammetric and computer vision methods have emerged (e.g., Knuth et al., 2023; Dehecq et al., 2020; Ghuffar et al., 2022), but their performance and limitations have not yet been evaluated in a consistent way.

The ongoing “Historical Images for Surface Topography Reconstruction Intercomparison eXperiment (Historix)” project aims at comparing existing methods for processing stereoscopic historical images and harmonizing processing tools.

Within this experiment, participants are provided with a set of historical images and available metadata and invited to return a point cloud and estimated camera parameters. We selected two study sites near Casa Grande, Arizona, and south Iceland, chosen for their  good availability of historical images and variety of terrain types. For each site, we selected 3 sets of film-based images acquired in the 1970s or 80s, overlapping in space and time: aerial images with fiducial marks from publicly available archives and 2 image sets from the American Hexagon (KH-9) reconnaissance satellite missions acquired by the mapping camera (KH-9 MC) and panoramic camera (KH-9 PC). The submitted elevation data will be cross-validated across different image sets and participant submissions, as well as against reference elevation data over stable terrain. The spread in the retrieved elevations will be analysed with respect to image type, terrain type and processing methods to highlight the strengths and limitations of the different approaches.

In this presentation, we will introduce the experiment design, the selected benchmark dataset, the current methodologies and the preliminary results of the intercomparison. Finally, we will present some of the open-source code that exist or are being developed to process historical images.

How to cite: Dehecq, A., Knuth, F., Belart, J., Piermattei, L., Ressl, C., McNabb, R., and Godin, L.: Historical Images for Surface Topography Reconstruction Intercomparison eXperiment (Historix), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3936, https://doi.org/10.5194/egusphere-egu26-3936, 2026.

The Antarctic Peninsula (AP) is a hotspot of global warming, with pronounced atmospheric warming reported during the 20th century. Although it is critical in terms of climate change studies, the mass balance of glaciers prior to 2000 remains poorly constrained. Existing mass balance estimates are further characterized by high uncertainties due to a lack of observations. In contrast, more than 30000 historical images in archives are the sole direct observations to quantify past glacial changes and their contribution to sea-level rise. 

In this study, we present a unique, timestamped, high-resolution Digital Elevation Model (DEM) and orthomosaic dataset, derived from aerial imagery that covers about 12000 km2 area on the western Antarctic Peninsula and surrounding islands between 66–68° S. We used a film-based aerial image archive from 1989 acquired by the Institut für Angewandte Geodäsie (IfAG), and is kept in the Archive for German Polar Research at the Alfred Wegener Institute, Germany, to generate the historical DEMs and orthoimages. The historical DEMs were co-registered to the Reference Elevation Model of Antarctica (REMA) mosaic on stable terrain. Our historical DEMs have vertical accuracies better than 6 m and 8 m with respect to modern elevation data, REMA, and ICESat-2, respectively. We have made this dataset publicly available at  https://doi.org/10.5281/zenodo.16836526.

Initial mass balance estimates from DEM differencing of our 1989 DEM with recent surfaces from REMA strip DEMs show a near-constant ice mass despite widespread glacier frontal retreat and thinning. We hypothesize that low-elevation ice thickness loss in this period is largely compensated by higher surface mass balance in higher areas. However, this regime appears to be changing, with glaciers transitioning toward increased dynamic activity with enhanced mass loss, and higher ice fluxes.

How to cite: Thota, V. K., Seehaus, T., Knuth, F., Dehecq, A., Salewski, C., Farías-Barahona, D., and H.Braun, M.: Historical aerial imagery–derived Digital Elevation Models and orthomosaics for glacier change assessment in the western Antarctic Peninsula since 1989, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4849, https://doi.org/10.5194/egusphere-egu26-4849, 2026.

Quantifying pebble size, shape, and roundness is fundamental to
understanding sediment transport and abrasion in fluvial systems, yet
remains challenging in natural, densely packed settings.  Most existing
approaches rely on 2D imagery and therefore fail to capture true
three-dimensional morphology. Here, we present a curvature-based instance
segmentation framework for reconstructed surface meshes and demonstrate its
role as a key step enabling 3D roundness and orientation analysis.

In our approach, individual pebbles are detected directly from 3D surface
reconstructions using curvature features, without prior shape assumptions.
Validation against high-resolution reference models yields a high detection
precision of 0.98, with remaining errors mainly due to under-segmentation
in overly smooth reconstructions.  Estimates of 3D pebble orientation are
strongly controlled by the represented surface area, highlighting both the
potential and current limitations of orientation retrieval from incomplete
surface segments.

We illustrate how reliable segmentation allow downstream 3D shape and
roundness analyses that are not accessible in 2D, including curvature-based
surface metrics and volumetric descriptors. Example fluvial scenes
demonstrate that segmentation quality directly controls the stability of
roundness estimates and their geomorphic interpretation. Our results
establish curvature-based 3D pebble segmentation as a methodological
foundation for reproducible analyses of pebble shape, roundness, and
orientation in natural river systems.

How to cite: Rheinwalt, A. and Bookhagen, B.: Curvature-based pebble segmentation as a foundation for 3D roundness and orientation analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5922, https://doi.org/10.5194/egusphere-egu26-5922, 2026.

Currently available global Digital Elevation Model (DEM) surfaces are either derived from the stereoscopic exploitation of multispectral satellite imagery, point-wise laser altimetry measurements or the interferometric processing of bistatic synthetic aperture radar data, but only radar data allows the acquisition of a global product in a reasonable timeframe. The public private partnership of DLR and Airbus in the TanDEM-X mission paved the ground for the WorldDEM product line and its derivatives such as the Copernicus DEM. Both datasets are based on data acquisitions from December 2010 to January 2015, manual and semi-automated DEM editing procedures and represent a very accurate, very consistent and only pole-to-pole DEM data set. The Copernicus DEM is available with a free-and-open licence.

Various ecosystems such as the geosphere, biosphere, cryosphere and anthroposphere are subject to continuous changes which demand the monitoring of Earth’s topography in regular updates of global Digital Elevation Model data. The WorldDEM Neo product represents the successor of the aforementioned WorldDEM but is based on a fully-automated editing & production process and newer data: the on-going TanDEM-X mission is expected to operate until 2028 and has created an archive of up-to-date DEM scenes ready for integration into a new global DEM coverage (>90% of global landmass acquired between 2017 and 2021; ~60% of global landmass acquired again between 2021 and 2025). In conjunction with continuous improvements of the fully-automated production processes, a new global DEM coverage of WorldDEM Neo is produced early 2026. DEM applications such as the orthorectification of raw satellite imagery will benefit from the availability of an accurate and up-to-date global DEM dataset. Other applications such as multi-temporal 3D change analysis based on a single satellite mission (TanDEM-X) are possible and support the understanding of environmental changes thanks to the 3rd dimension. The rapid availability of the error-compensated WorldDEM Neo Digital Surface Model (DSM) and bare-ground Digital Terrain Model (DTM) after raw data acquisition serve various applications of global DEMs. Future acquisitions of the on-going TanDEM-X mission (until 2028) allow the processing of final and up-to-date DSM and DTM coverages at the end of the mission lifetime.

The presentation comprises a short look into the history with its manual & semi-automated DEM editing procedures. The main focus will be on the fully-automated production processes for truly global DSM & DTM coverages. Accuracy metrics, 3D change statistics between the different global coverages but also visual impressions of the various global DEM coverages will be addressed, too. On-going challenges with interferometry-based elevation data are part of an outlook and different error compensation strategies (e.g. height reconstruction from radar amplitude data based on machine-learning techniques) are highlighted.

How to cite: Fahrland, E. and Schrader, H.: Updating and upgrading a global Digital Elevation Model - the fully automated production of WorldDEM Neo with acquisitions until 2025, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6660, https://doi.org/10.5194/egusphere-egu26-6660, 2026.

Avalanches are critical contributors to the mass balance and spatial accumulation patterns of mountain glaciers. While gravitational snow redistribution models predict high localized accumulation, these predictions lack field validation due to the difficulty of monitoring highly dynamic avalanche cones. Here, we present two years of high-resolution monitoring of a large avalanche cone in the accumulation area of Argentière Glacier (French Alps). To capture these dynamics, we employed a multi-sensor approach: Uncrewed Aerial Vehicle (UAV) surveys and a time-lapse photogrammetry array consisting of 7 low-cost cameras deployed ~1 km away from the cone. The distance of the sensors from the surveyed area, its geometry (>30°), its surface characteristics (smooth snow surface) and the absence of fixed stable terrain due to the surrounding headwalls being episodically covered in snow made this environment particularly challenging for the photogrammetry methods applied. Point clouds and Digital Elevations Models were produced at a two-week resolution using Structure-from-Motion photogrammetry in Agisoft Metashape v1.8.3. with the alignment being constrained with Pseudo Ground Control Points. We could further co-register all point clouds to a September UAV acquisition with the Iterative Closest Point algorithm from the open-source project Py4dgeo, using automatically-derived stable ground from the RGB information of the images.

Methodological validation shows that while side-looking time-lapse photogrammetry captures the overall trend, it tends to underestimate elevation changes compared to UAV data, with biases up to 1.8 m and standard deviations of 2–6 m. Winter-time acquisitions with low light conditions over smooth snow surfaces also lead to reduced correlation over the cone. Despite these uncertainties, our results reveal extreme spatial variability in accumulation. The top of the cone is the most active zone, exhibiting elevation changes of ~30 m annually and a strong accumulation of 60 m w.e. between March 2023 and 2025 when accounting for the ice flow—roughly 15 times the annual mass balance recorded by the GLACIOCLIM program in the nearby accumulation area not affected by avalanche deposits. We identify a topographical threshold for snow storage: the upper cone fills early in the season until reaching a critical slope of ~35°, after which subsequent avalanches bypass the apex to deposit mass at the cone’s base. From May onwards, mass redistribution is further modulated by the development of surface channels. Our findings demonstrate that time-lapse photogrammetry is a viable tool for monitoring dynamic glacier surfaces and provide rare empirical evidence of the dominant role avalanches play in glacier mass budgets.

How to cite: Kneib, M., Wagnon, P., Arnaud, L., Balmas, L., Laarman, O., Jourdain, B., Dehecq, A., Le Meur, E., Brun, F., Kneib-Walter, A., Santin, I., Charrier, L., Faug, T., Mazzotti, G., Rabatel, A., Six, D., and Farinotti, D.: Use of time-lapse photogrammetry to capture substantial accumulation rates on an on-glacier avalanche deposit , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9007, https://doi.org/10.5194/egusphere-egu26-9007, 2026.

River bank erosion represents a dynamic geomorphic hazard, particularly in meandering channels where migration rates threaten critical infrastructure and agricultural land. While our previous work on the Sajó River (Hungary) established a novel, low-cost monitoring framework utilizing Raspberry Pi (RPi) cameras for near-continuous observation, the reliability of photogrammetric reconstruction under uncontrolled outdoor conditions remains a critical challenge. This study presents a systematic evaluation of the accuracy constraints inherent in automated Structure-from-Motion (SfM) processing pipelines, with a specific focus on optimizing image alignment across a wide range of scene conditions.

To determine the robustness of RPi imagery, we conducted a comprehensive sensitivity analysis of the SfM-based image alignment phase. We systematically tested over 120 variations of processing parameters, manipulating keypoint and tie-point limits, upscaling factors, and masking strategies. The implementation of rigorous masking was critical, as the imagery is geometrically challenging: the moving river surface in the foreground and the sky in the background occupy the majority of the field of view, leaving only a narrow, static fraction of the image relevant for reliable 3D reconstruction. These combinations were evaluated against a dataset representing the full range of environmental variability, including clear, cloudy, dark, foggy, overexposed, and rainy conditions, as well as distinct hydrological states such as low flows, flood events, and snow cover.

Preliminary results indicate that a specific balance of 30,000 keypoints and 5,000 tie points (ratio 6.0) optimizes reconstruction fidelity, achieving an RMS error of 0.75 pixels under clear weather conditions. Notably, the system demonstrated unexpected robustness in low-light scenarios, maintaining consistent error margins of 1.17–1.18 pixels across various configurations. Conversely, scaling up these limits beyond the optimum yielded diminishing returns, confirming that higher computational loads do not necessarily equate to improved geometric accuracy. Furthermore, we applied gradual selection algorithms to filter sparse point clouds, removing unreliable points based on reconstruction uncertainty to isolate the most geometrically valid features.

The crucial final phase of this research bridges the gap between digital reconstruction and physical reality. We validate the optimized SfM-based point clouds by comparing them directly against high-precision Terrestrial Laser Scanning (TLS) data acquired during two previous campaigns and upcoming field surveys. This multi-temporal comparison allows us to quantify specific error margins for volumetric and horizontal material displacement calculations. By defining these accuracy constraints, we establish a validated protocol for calculating erosion volumes during high-flow events, ensuring that automated, low-cost monitoring systems can provide actionable, high-precision data for river management even under adverse environmental conditions.

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The research was funded by the DAAD-2024-2025-000006 project-based research exchange program (DAAD, Tempus Public Foundation).

How to cite: Bertalan, L., Kovács, L., Duran Vergara, L. C., Abriha, D., Krüger, R., Blanch Gorriz, X., and Eltner, A.: Optimizing SfM workflows for continuous river bank monitoring: evaluating image alignment accuracies across diverse environmental conditions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9167, https://doi.org/10.5194/egusphere-egu26-9167, 2026.

Long-term observations of glacier mass change provide a key indicator of atmospheric warming and are essential for understanding glacier behaviour and responses to climate forcing. Archived aerial photographs represent an underutilised source of historical information from which three-dimensional surface geometry can be reconstructed to quantify past glacier change. This approach is particularly valuable in Antarctica, where surface-elevation change prior to the 1990s remains poorly constrained due to limited pre-satellite altimetry and a scarcity of reliable Ground Control Points (GCPs). As a result, historic mass-balance estimates have largely relied on climate reanalysis and modelling.

Advances in photogrammetric techniques have substantially improved the efficiency and accuracy of Digital Elevation Models (DEMs) derived from historical aerial imagery. Here, we present a newly compiled inventory of Antarctic aerial surveys conducted throughout the twentieth century, documenting their spatial and temporal coverage to identify regions suitable for DEM reconstruction. Then, building on established workflows, we show newly constructed DEMs for three glaciers that formerly fed the Larsen A Ice Shelf on the Antarctic Peninsula, capturing surface geometry both before and after its collapse in 1995. These reconstructions reveal heterogenous glacier responses to reduced buttressing, controlled by local morphology and consistent with previous regional observations.

How to cite: Rowe, E., Willis, I., and Fenney, N.: Compiling an Inventory of Historic Antarctic Aerial Photographs to Measure Long-Term Glacial Mass Balance Change from Digital Elevation Models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13015, https://doi.org/10.5194/egusphere-egu26-13015, 2026.

As part of the DFG research group “Sensitivity of high alpine geosystems to climate change since 1850” (SEHAG), high-resolution multibeam sonar data was collected from the proglacial Grastallake in the Ötztal valley during a boat survey in the summer of 2025. The Grastallake has an area of approximately 63,000 m², a maximum depth of approximately 16 m, and lies at an altitude of 2,584 m. The lake is situated in a former cirque, and its shores and the surrounding are partly composed of loose material and partly of solid rock. In the western part, there is a large whaleback with already known Egesen-moraines on top. On the southern and eastern shores, larger active debris flow cones are coupled to the lake, with meltwater runoff from the higher Grastalferner glacier flowing into the lake as a perennial stream via the eastern debris flow cone. Due to the permanent inflow from the glacier and the topographic conditions of the catchment area, the eastern debris flow cone is very active and has intensively been reshaped by several extreme debris flow events during the last years.

The bathymetric data was collected using a Norbit multibeam sonar (WBMS), which was supplemented by an SBG INS system (dual GNSS patch antenna system, SBG Eclipse D) by Kalmar Systems. Since the underwater topography of the lake was unknown and its high turbidity due to the glacier inflow, the first step was to conduct a rough survey of the lake. This step made it possible to create a coarse depth map on site in order to identify spots with shallow water, determine the system settings, and draw up a navigation plan along strips. After field work the recorded data was processed using Quinertia for trajectory calculation and Opals for strip adjustment. This resulted in a final 3D point cloud with an average point density of 400 points per square meter, which was converted to raster data in order to perform spatial analyses.

Using the data, geomorphological forms were mapped in a first step. In addition to a previously unknown late glacial moraine section, the underwater deposits of recent debris flows became visible. In addition to mapping, geomorphological structures were used for spatial analysis, such as comparing the depositions of debris flows above and below the water. Since the data is very well suited for mapping underwater structures, this case study demonstrates the enormous potential of bathymetric data acquired by multibeam sonar measurements, that has rarely been used for geomorphological studies to date. Multitemporal analysis in the sense of a 4D analysis could only be carried out to a limited extent in this case study. However, with the data now available, multitemporal analysis, i.e., quantification of sediment input into lakes, will also be possible in the future. This would then enable assessments to be made of the hazard potential of newly formed lakes in the proglacial area and of their lifespan. 

How to cite: Haas, F., Stark, M., Rom, J., Dammert, L., Kohlhage, T., Himmelstoss, T., Kara-Timmermann, D.-E., Altmann, M., Surrer, C., Baumgartner, K., Fischer, P., Betz-Nutz, S., Heckmann, T., Pfeifer, N., Mandlburger, G., and Becht, M.: Using high-resolution bathymetric data from a multibeam sonar acquisition to map and analyse geomorphical underwater structures in the proglacial Grastallake in the Horlachtal valley/ Ötztal Alps, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13875, https://doi.org/10.5194/egusphere-egu26-13875, 2026.

In recent years, forest management and inventory have increasingly relied on handheld personal laser scanners (H-PLS) for capturing flexible three-dimensional data. These systems have become essential for extracting critical tree attributes, such as diameter at breast height (DBH) and tree height. Most traditional H-PLS systems utilize Simultaneous Localization and Mapping (SLAM), which fuses LiDAR and Inertial Measurement Unit (IMU) data to reconstruct environments. However, SLAM is based on relative sensor measurements, which inherently causes accumulated errors and trajectory drift. In complex forest environments, similar-looking stems and moving vegetation can further confuse the mapping process, resulting in distorted point clouds or duplicated stems that reduce the accuracy of extracted tree attributes.

While Global Navigation Satellite System (GNSS)-based Real-Time Kinematic (RTK) positioning provides centimetre-level absolute accuracy and usually drift-free trajectories, its application in forestry is critically hindered by signal obstruction in dense canopies. The integration of GNSS-RTK and SLAM offers a robust and synergetic solution to these challenges, allowing one method to compensate for the failures of the other. A promising development in this field is an H-PLS system that integrates GNSS-RTK, IMU, LiDAR, and camera measurements to generate georeferenced point clouds directly in the field. This hybrid approach utilizes LiDAR and camera data to maintain positioning during GNSS outages and utilizes RTK information to re-initialize and correct the trajectory once the signal is restored.

Our study evaluates whether this integrated GNSS-RTK SLAM approach improves point cloud geometry and tree attribute extraction compared to traditional SLAM methods without GNSS integration. We conducted a field campaign in a mixed forest stand during the leaf-off period to simulate realistic operating conditions with alternating GNSS visibility. The performances of a SLAM-only and a SLAM + GNSS-RTK H-PLS were validated against highly accurate terrestrial laser scanning (TLS) reference data. The analysis involved tree segmentation to assess individual tree identification and the derivation of DBH, stem positions, and tree heights. Furthermore, we investigated internal geometric quality by analysing local noise levels using cross-sectional residuals relative to fitted circles and assessed spatial homogeneity to identify artifacts like duplicated stems or gaps.

Initial results indicate that the SLAM + GNSS-RTK H-PLS system provides DBH estimates comparable to TLS, with observed differences of 6.3 mm and 1.17 cm for major and minor axes, respectively. Despite slight overestimations due to scattering, the significantly reduced acquisition time makes this integrated system an efficient alternative for forestry applications. These findings contribute to a better understanding of how integrated positioning systems can enhance mobile laser scanning workflows and support the development of autonomous, high-precision forest mapping solutions.

How to cite: Rünger, C., Binapfl, S., Maiwald, F., Krüger, R., and Eltner, A.: High-precision point cloud generation for forest inventory: Integrating GNSS-RTK and SLAM for handheld laser scanning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17031, https://doi.org/10.5194/egusphere-egu26-17031, 2026.

Many topographic scenes demonstrate complex dynamic behavior that is difficult to map and understand. A terrestrial laser scanner fixed on a permanent position can be used to monitor such scenes in an automated way with centimeter to decimeter quality at ranges of up to several kilometers. Laser scanners are active sensors, and can continue operation during night. Their independence from surface texture properties ensures in principle that they provide stable range measurements for varying surface conditions.

Recent years have seen an increase in the employment of such systems for different applications in environmental geosciences, including forestry, glaciology and geomorphology. This employment resulted in a new type of 4D topographic data sets (3D point clouds + time) with a significant temporal dimension, as such systems can acquire thousands of consecutive epochs.

However, extracting information from these 4D data sets turns out to be challenging, first, because of insufficient knowledge on error budget and correlations, and second, because of lack of algorithms, benchmarks, and best-practice workflows.

The presentation will showcase recently active systems that monitored a forest, a glacier, an active rockfall site and a sandy beach respectively. Data from these systems will be used to illustrate different systematic challenges that include instabilities of the sensor system, meteorological and atmospheric influence on the data product and the maybe surprising need for alignment of point clouds from different epochs.

In addition, different ways to extract information from these 4D data sets will be discussed, in connection with particular applications. While bi-temporal change detection is often a starting point for exploring 4D data, several methods are being developed that truly exploit the extensive time dimension, including tracking, trend analysis, time series clustering and spatio-temporal region growing.

Lessons learned from experiences with these systems in different domains lead to several recommendations for future employment considering field of view design, auxiliary sensors (e.g. IMU, camera, weather station) and the possible deployment of low-cost alternatives, thereby providing a view on the near future of permanent laser scanning.

Reference

Lindenbergh, R., Anders, K., Campos, M., Czerwonka-Schröder, D., Höfle, B., Kuschnerus, M., Puttonen, E., Prinz, R., Rutzinger, M., Voordendag, A & Vos, S. (2025). Permanent terrestrial laser scanning for near-continuous environmental observations: Systems, methods, challenges and applications. ISPRS Open Journal of Photogrammetry and Remote Sensing, 17, 100094. DOI: 10.1016/j.ophoto.2025.100094

How to cite: Lindenbergh, R., Vos, S., and Hulskemper, D.: Permanent terrestrial laser scanning for environmental monitoring, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17484, https://doi.org/10.5194/egusphere-egu26-17484, 2026.

Beachrocks are cemented coastal deposits formed within the intertidal zone by the precipitation of magnesium-rich calcium carbonate. They constitute important paleogeographic and paleoclimatic markers, as they allow the reconstruction of past shoreline evolution. In addition, beachrocks influence current coastal dynamics and represent valuable geological heritage and ecological reservoirs that require preservation.

This study focuses on a sequence of multiple beachrock levels located along the Catalan Coast (NE Iberian Peninsula). The system consists of a complex sequence of submerged beachrocks with a wide formation range, situated at water depths between −0.25 m and −48 m below the current sea level. These deposits exhibit lateral continuity of up to 4.5 km and are characterized by reduced thicknesses and low geomorphic expression. The underlying substrate is composed of unconsolidated marine sediments. In certain sectors, a spatial overlap with Posidonia oceanica meadows occurs.

The aforementioned characteristics hinder their cartographic representation using traditional methods, such as aerial image interpretation and hillshade maps derived from bathymetric data, particularly for thin structures located at greater depths and in areas where Posidonia oceanica meadows are present.

The aim of this study is to evaluate the usefulness of the Red Relief Image Map (RRIM) method as an alternative quantitative terrain visualization tool for the cartography of submerged beachrocks. This method is based on the quantitative attribute openness, which expresses the degree of dominance or enclosure of a location on an irregular surface and enhances concave (negative openness) and convex (positive openness) features. Using this attribute, the RRIM method combines three main elements: topographic slope, positive openness and negative openness, allowing the visualization of subtle, low-relief topographic structures on apparently flat surfaces.

Using this approach, this study aims to improve the identification and cartographic delineation of submerged beachrock levels and to define optimal visualization parameters that contribute to a better understanding of the beachrock sequence.

How to cite: Vicente, M.-A., Mencos, J., and Roqué, C.: Testing the Red Relief Image Maps methodology to enhance the beachrock cartography in Torredembarra coast (Catalan coast, West  Mediterranean Sea), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17571, https://doi.org/10.5194/egusphere-egu26-17571, 2026.

How to cite: Kugler, L., Rada, C., Webster, C., Wegner, J. D., Berthier, E., and Piermattei, L.: Long-term glacier elevation change at Gran Campo Nevado since 1945 , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17927, https://doi.org/10.5194/egusphere-egu26-17927, 2026.

Badlands are among the most rapidly developing landscapes and exhibit a significant degree of geomorphological activity. In semi-arid/ sub-humid landscapes, specific precipitation dynamics result in particularly rapid geomorphological development. This applies in particular to land cover and geomorphology. This study employs quantitative, multi-temporal analysis to examine the spatio-temporal changes in a sub-humid calanchi badland in the upper Val d'Orcia (Italy) over a period of ten years (2014-2024). Particular emphasis lies on the dynamics of geomorphological processes and topographical changes, while considering the variables of vegetation and precipitation. The analysis encompasses both extreme events and prolonged rainfall lasting several days, which are the primary factors for surface changes in subhumid badlands. The utilisation of UAS SfM-MVS in conjunction with precise dGNSS measurements facilitates high-resolution change detection and landform analysis across five distinct observation periods, each spanning two years (= five DoD). The interactions between vegetation and geomorphological processes are investigated using a semi-automatic mapping approach based on the Triangular Greenness Index (TGI) and the interpretation of topographical changes (DoD). The vegetation analysis are based on high-resolution orthomosaics with a resolution of 0.05 m, while the geomorphic change detection analysis is carried out on 2.5D rasterised digital surface models with a resolution of 0.25 m. The major results are as follows: The mean slope gradient of the entire study site remained largely stable despite certain areas showing enhanced geomorphic activity. The DoD analysis revealed four 'geomorphic hot spots', areas of enhanced geomorphic activity and sediment contribution from the tributaries to the main valley (the major deposition area). The annual erosion rates vary between -0.4 cm (2018-2022) and -4 cm (2022-2024). The observed topographic changes can be attributed primarily to high-magnitude events (complex landslides and debris-like flows) that occur irregularly. The multi-temporal mapping of landforms has revealed a significant reduction in water erosion, with a 50% decrease observed from 35% in 2014 to 17% in 2024. Furthermore, the combination of 2D-mappings and 2.5D DoD-analysis enabled the documentation of a geomorphological process previously unknown in badland areas, namely gravitational bulging. This describes the deformation of sediments in lower-lying clay layers as a response to water infiltration, high swelling capacities of clays and the pressure exerted by the sediment packages lying above them. A significant increase in vegetation cover has been observed, particularly in areas designated as potentially moist and gentle terrain, often the deposition areas from the previous period. In general, vegetation underwent a gradual transition, evolving from a fragmented to a continuous structure, primarily due to the widespread colonisation of the main valley and the landslide pathways.  Although the area affected by erosion processes decreased over the course of the study period, erosion rates remained relatively constant. This indicates a shift from high-frequency to high-magnitude processes in the most recent observation period. Overall, the phase under consideration in this study (2014-2024) can be characterised as a phase of badland stabilisation.

How to cite: Stark, M., Sannino, A., Trappe, M., Rom, J., Forster, J., Kahlenberg, G., Haas, F., and Vergari, F.: From badland to bushland? Analysis of geomorphic process dynamics and vegetation development in a sub-humid calanchi area based on high-resolution UAS data (2014-2024)., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18399, https://doi.org/10.5194/egusphere-egu26-18399, 2026.

The recovery of historical topography from analogue aerial archives has has become a well-established workflow in geosciences, unlocking high-resolution records of topographic change that were previously inaccessible. However, the standard practice for sharing these results relies on static FTP servers or raw file downloads. Consequently, these datasets often remain difficult to discover, particularly for researchers from other disciplines who cannot easily assess the spatial coverage or relevance of the archive through static file lists. Furthermore, existing web-based visualization solutions often require complex database configurations and advanced full-stack development skills, rendering them inaccessible for many geoscience research groups lacking dedicated software engineers.

In this work, we present a lightweight, open-source web application designed to support the publication of historical photogrammetric data. The design prioritizes portability and ease of deployment for non-developers. Unlike complex Content Management Systems (CMS) that rely on heavy database backends, our tool utilizes a streamlined file-based ingestion pipeline. Researchers can deploy a fully interactive instance by populating a directory structure with standard geospatial vector formats (e.g., Shapefiles, GeoJSON) and point cloud data. The Node.js-based backend automatically parses these inputs to configure the visualization interface, thereby eliminating the need for manual database administration.

We demonstrate the capabilities of the website using a dataset from the Antarctic TMA archive with ~ 250.000 images. The resulting interface facilitates spatio-temporal discovery through an interactive map that visualizes survey footprints, including the residuals between metadata-derived and SfM-estimated positions. This allows users to rapidly assess geometric quality and survey coverage. To extend the platform beyond simple 2D mapping, we present the architectural integration of Potree for browser-based 3D visualization. We discuss the workflow for streaming massive point clouds to the client, a feature designed to transform the website from a passive gallery into an active analytical tool for measurement and validation. Finally, we address the challenge of data distribution by outlining the implementation of a bulk-download utility, structured to allow users to filter and request specific subsets of raw imagery, associated metadata and processed data based on their visual selection.

By providing a self-contained, low-dependency solution, we aim to shift the community standard from static archiving to dynamic, interactive exploration. This tool allows geoscientists to easily share their historical images and reconstructions and make their data truly accessible to the broader scientific community without the overhead of custom software development.

How to cite: Dahle, F., Lindenbergh, R., and Wouters, B.: From Static to Dynamic: Modernizing the Sharing of HistoricalPhotogrammetry Datasets, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19445, https://doi.org/10.5194/egusphere-egu26-19445, 2026.

Desert kites are large prehistoric hunting traps typically composed of two long, low stone walls that converge toward an enclosure.  These structures are widely distributed across the arid and semi-arid margins of the Middle East and Central Asia, exhibiting substantial variability in size, geometry, construction techniques, and topographic setting. To better understand their functionality from the Neolithic to sub-contemporaneous times, terrestrial laser scanning has increasingly been used to capture high-resolution three-dimensional representations of desert kites, enabling detailed characterization of their construction and local terrain setting. However, the kites’ subtle expression, their large spatial extent, and their progressive blending into the natural surface complicate their detection. These difficulties are further exacerbated by variable point density resulting from the alignment of multiple terrestrial scans, unavoidable occlusions caused by topography or vegetation, and the sheer volume of data produced by high-resolution ground-based surveys.  Together, these factors make the reliable identification and analysis of desert kite features within raw terrestrial point clouds a challenge, which requires extensive manual intervention and expert interpretation.

In this study, I present an automated, machine-learning-based approach for highlighting desert kite features directly within 3D point clouds derived from terrestrial laser scanning, without the need for manual annotation or labelled training data. The proposed method is based on the premise that the kites' structures introduce geometric irregularities (anomalies) relative to the surrounding natural surface. Rather than explicitly modelling the kite's form  or imposing predefined shape descriptors, the method learns a representation of the underlying terrain surface directly from the point cloud. This learned representation is then used to reconstruct the surface, which is subsequently compared to the original terrestrial measurements. Local deviations between the reconstructed surface and the original point cloud are quantified, with larger reconstruction errors interpreted as potential surface anomalies indicative of the kite's features. 

The proposed workflow is fully data-driven and unsupervised. It does not rely on prior knowledge of kite geometry, site-specific heuristics, or expert-defined thresholds. Instead, the learning process adapts to the local surface characteristics captured in the input dataset, making it robust to variations in resolution, occlusions, and terrain complexity commonly encountered in terrestrial laser scanning surveys. 

The findings demonstrate that surface-reconstruction-based anomaly detection offers a promising pathway for the automated identification of desert kite features in terrestrial 3D point clouds. More broadly, the approach is applicable to archaeological structures that exhibit weak or subtle geometric signatures. By reducing dependence on manual interpretation and labelled datasets, the method supports more objective, scalable, and reproducible analyses of archaeological landscapes, particularly in complex terrain where anthropogenic features are embedded within natural surfaces.

How to cite: Arav, R.: Detecting desert kites in 3D point clouds by learning anomalies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20499, https://doi.org/10.5194/egusphere-egu26-20499, 2026.

Despite significant advancements in landslide monitoring, landslides occurring on densely forested slopes remain largely unexplored. While conventional subsurface characterization methods (e.g., DPH, CPT, percussion drilling) are often impractical due to limited accessibility and steep rugged terrain, surficial analyses using remote sensing techniques frequently face challenges in capturing high-resolution ground surface data due to occlusion caused by dense vegetation cover as well as technical limitations.
Although trees and forests are generally acknowledged to reduce the probability of landslide occurrence, they are unlikely to prevent or substantially mitigate deep-seated landslides or failures on very steep slopes. Instead, trees may serve as proxies of landslide activity, potentially improving the understanding and monitoring of densely forested slopes. Affected by slope movements, trees experience external growth disturbances and develop characteristic growth anomalies that can be partly attributed to underlying landslide processes.

Multiple studies have demonstrated the feasibility of extracting such external growth disturbances, primarily stem tilting, by assessing the inclination and curvature of tree stems in LiDAR point clouds, greatly building upon previous forestry-related studies exploring the mapping, classification, and derivation of stem parameters such as height and diameter from digital twins. However, the potential to extract externally visible eccentric growth patterns in stem cross-sections at heights of maximum bending, analogous to dendrogeomorphologic tree-ring analyses, as a proxy for landslide activity has not yet been explored. Additionally, the classification of overall tree shape may provide valuable insights into the characteristics of underlying slope movements, but, to the best of the author’s knowledge, this has not been addressed in previous research.

To investigate the potential of automatically extracting tree shape and stem eccentricity from LiDAR data, and to evaluate their suitability as proxies of landslide activity, we introduce an improved two-stage processing pipeline for tree identification and extraction, along with a dedicated framework for digital dendrogeomorphology. Building upon previous work, we compute normal vectors of locally fitted planes and projected point densities to separate trees from the point cloud. To enhance the extraction of complex shaped trees (e.g., S-shaped or pistol-butted) characteristic of landslide-prone slopes, we introduce dynamically adjusted normal vector thresholds derived from estimated stem inclination. After segmenting tree stems from the point cloud, ellipses are fitted at configurable height intervals to determine cross-section centroids. These centroids are then connected as vertices of a 3D polyline, which is subsequently smoothed using a natural spline to represent the generalized stem geometry. Based on the curvature of the resulting polyline, the height of maximum bending is identified, and the corresponding cross-section eccentricity is extracted. In addition, the curvature of the polyline is used to categorically classify overall tree shape.

Our digital dendrogeomorphology approach applied to 3D point clouds enables accurate extraction of stem eccentricity, even for complex tree shapes typical of landslide-prone slopes. When paired with automated tree-shape classification, these data offer insights into slope movement and improve understanding of landslide processes in densely forested environments.

How to cite: Kamaryt, T.-H. and Müller, B.: Tree Geometry as a Potential Proxy for Landslide Activity in Densely Forested Slopes: A LiDAR-Based Digital Dendrogeomorphology Approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21238, https://doi.org/10.5194/egusphere-egu26-21238, 2026.

Large-scale infrastructure development in mountain regions produces significant changes in slope morphology and surface processes. However, stability assessments conducted after construction often rely on static or short-duration evaluations. These approaches tend to assume an immediate geomorphic adjustment to human disturbance, which can overlook delayed and nonlinear responses of hillslopes. This study examines terrain adjustments that occur with a time delay following major construction activities in complex mountainous settings. The analysis is based on a series of high-resolution topographic datasets obtained through repeated LiDAR surveys along the Sibiu - Pitești motorway corridor in the Southern Carpathians of Romania. Changes in terrain configuration caused by excavation, filling, drainage alteration, and the unloading of slopes are identified by comparing elevation models and terrain metrics. Instead of focusing solely on deformation located at the site of intervention, the study investigates terrain responses that appear later and in areas situated upslope or laterally from the engineered zones. Findings show that slope instability and surface reorganization often emerge after a measurable time delay, typically reactivating existing geomorphic features such as drainage pathways, slope breaks, and erosional forms. These responses are not random but show a strong dependence on prior landscape conditions and the type of construction-related disturbance. The results emphasize the limitations of early assessments performed shortly after construction, which may fail to capture landscape dynamics relevant for landslide initiation. The study demonstrates the usefulness of repeated LiDAR mapping for detecting evolving terrain responses in engineered mountain landscapes and supports the integration of time-sensitive processes into hazard assessment strategies.

How to cite: Al-Taha, W., Andra-Topârceanu, A., and Mustățea, S.: Delayed slope response to infrastructure-induced landscape modifications in mountainous terrain revealed by high-resolution LiDAR analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21758, https://doi.org/10.5194/egusphere-egu26-21758, 2026.

As glaciers retreat, permafrost degrades, and mountains destabilize, modern landscape evolution is increasing the potential for catastrophic events, such as the Birch Glacier collapse on May 28, 2025. To improve our understanding of mass movements in mountainous regions and support future hazard assessment and risk mitigation efforts, we are generating time series of glacier surface elevation change from historical aerial photography provided by the Swiss Federal Office of Topography (Swisstopo). 

In this case study, we leveraged multi-temporal photogrammetric reconstruction and Digital Elevation Model (DEM) coregistration techniques, implemented in the Historical Structure from Motion (HSfM) pipeline, to generate an ~80-year record of self-consistent DEMs and orthoimage mosaics from analog film imagery collected over the Birch Glacier between 1946 and 2010. From 1985 until 2010 we generated nearly annual surface measurements, making this a unique and remarkably dense historical time series. The time series is augmented with modern surface measurements generated from linescan and UAV imagery collected during the period of 2010 to 2025. To quantify the uncertainty of elevation change measurements we compute residuals with respect to the swissSURFACE3D elevation over stable ground, defined by the swissTLM3D land surface classification. The reconstructed time series provides geometric constraints to precisely model the preconditioning phase leading up to the May 2025 Nesthorn-Birchglacier hazard cascade, which may help mitigate future risks in mountainous terrain (see Jacquemart et al. 2026 in GM3.1)

How to cite: Knuth, F., Hodel, E., Heisig, H., Marty, M., Jacquemart, M., Bauder, A., Simmen, J.-L., and Farinotti, D.: Automated photogrammetric reconstruction of Birch Glacier, Switzerland (1946–2025): A high-density time series of topographic change preceding catastrophic glacier collapse, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22072, https://doi.org/10.5194/egusphere-egu26-22072, 2026.

Authors:

Ezeaba Assumpta¹, Dallan Eleonora¹, Vohnicky Petr¹, Borga Marco¹

¹ Department of Land, Environment, Agriculture and Forestry, University of Padova, Legnaro, Italy

Type of presentation:

Poster

Title:

Interplay Between Event Frequency and Intensity in Future Rainfall Erosivity revealed by Convection-permitting climate models

Abstract:

Soil erosion represents a critical environmental and economic challenge facing agricultural landscapes, and its severity could be amplified by the rising intensity of extreme rainfall in a warming climate. Rainfall erosivity, a key driver of erosion, depends on both rainfall intensity and the frequency of erosive events, making it highly sensitive to their ongoing and future changes. High resolution convection-permitting models (CPMs) offer enhanced representation of sub-daily rainfall extremes, yet their application to soil erosion studies remains limited.

This work assesses the skill of an hourly CPM in reproducing historical rainfall erosivity in a Mediterranean Island, Sicily, and evaluates its future changes under RCP4.5 and RCP8.5 scenarios. Modelled rainfall was first bias-corrected using intensity thresholds and scaling factors derived from high temporal-resolution observations. The CPM shows underestimate in maximum rainfall intensity and erosive event frequency, and thus in mean annual erosivity, especially in lowland and coastal areas. These biases highlight challenges in simulating short-duration convective events, sea-land interactions, and mismatches between point-based and gridded datasets. Future projections show divergent outcomes: under RCP4.5 moderate frequency decrease combines with higher intensities leading to a moderate net increase in erosivity, whereas under the RCP8.5 scenario a marked (17%) reduction in event frequency dominates the signal, yielding lower future erosivity despite rainfall intensification.

The results demonstrate that bias correction procedures should consider topographic dependence and different erosivity-related variables, and that future erosivity cannot be inferred from intensity changes alone; event frequency is equally relevant. Incorporating high-resolution climatic models and explicitly accounting for frequency-intensity interactions are therefore essential for robust erosion risk assessments and climate adaptation strategies.

This study was carried out within the RETURN Extended Partnership and received funding from the European Union Next‐GenerationEU (National Recovery and Resilience Plan—NRRP, Mission 4, Component 2, Investment 1.3—D.D. 1243 2/8/2022, PE0000005); and within the Space It Up project funded by the Italian Space Agency, ASI, and the Ministry of University and Research, MUR, under contract n. 2024-5-E.0 - CUP n. I53D24000060005.

How to cite: Ezeaba, A., Dallan, E., Vohnicky, P., and Borga, M.: Interplay Between Event Frequency and Intensity in Future Rainfall Erosivity revealed by Convection-permitting climate models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1632, https://doi.org/10.5194/egusphere-egu26-1632, 2026.

Wave-induced seabed liquefaction is a common factor leading to submarine instability, primarily occurring in silty seabeds. Under wave action, the pore water pressure within the seabed continuously increases. When the pore water pressure approaches or exceeds the total stress of the soil, the effective stress of the soil tends toward zero, resulting in liquefaction. Currently, most models of seabed dynamic response are based on macroscopic constitutive equations derived from Biot’s consolidation theory, making it difficult to accurately reveal the mesoscale mechanisms of seabed behavior under wave loading. This study employs a coupled numerical approach integrating the Lattice Boltzmann Method (LBM), the Immersed Boundary Method (IBM), and the Discrete Element Method (DEM) to systematically investigate the dynamic response and liquefaction process of a seabed under wave action. In this model, DEM is used to describe the motion and interactions of seabed sediment particles, LBM is applied to simulate fluid flow behavior, and IBM handles the coupling effects between particles and the fluid. Additionally, to improve computational efficiency, local grid refinement is applied near the seabed region, enhancing overall calculation performance. Using this coupled model, the periodic variations of wave-induced pore water pressure and effective stress in the seabed are studied, and the simulation results are validated against experimental data. The results show good agreement between simulations and experiments, accurately reflecting the dynamic response characteristics of the seabed under wave action. The model not only reveals the interaction mechanisms between soil particles and pore fluid from a microscopic perspective but can also be further extended to study the coupled effects of liquefaction and scour on near-bed sediment transport, offering significant theoretical insights and practical engineering value.

How to cite: Zhang, J., Zhang, Q., Li, Z., and Liu, G.: A Fully-Resolved Simulation Study of Seabed Liquefaction and Dynamic Response Using a Coupled LBM-IBM-DEM Approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2481, https://doi.org/10.5194/egusphere-egu26-2481, 2026.

There are no theoretical formulas that can accurately predict the sand transport rate (Q_m) over the Gobi surface. We report herein high-frequency field observations of wind-blown sand processes over the Gobi surface under extremely high winds in eastern Xinjiang, China. The results reveal that the power-law exponent of the scaling relationship between Qₘ and friction wind velocity (u_τ) in the extremely high winds with high gravel coverage Gobi area can reach 15.51, significantly exceeding that on sandy surfaces. Meanwhile, there is a favorable power-law between Q_m and the fluctuation intensity of the vertical wind velocity (I_w), whereas the correlation between Qₘ and the streamwise fluctuation intensity (I_u) is weak. Therefore, I_w has a significant application in constructing the prediction model for Qₘ over such Gobi surfaces. This study provides a new insight into the quantitative analysis of the aeolian transport over the windy Gobi areas.

How to cite: Wang, T.: Sand Transport Rate and Turbulent Fluctuation in AeolianTransportation Over the Gobi Surface Under ExtremelyHigh Winds, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2690, https://doi.org/10.5194/egusphere-egu26-2690, 2026.

Field observations in the Jiangjia Ravine show that surge characteristics evolve systematically along the flow path. As the flows transition from steep upstream slopes to gentler downstream reaches, surge forms shift from high-frequency low-amplitude surges to low-frequency high-amplitude surges. To explain the spatial evolution of surges, we develop a mechanistic model governed by slope geometry and yield stress. The shear stress can fall below the yield stress at slope breaks, temporarily blocking the flow. Subsequent surges with higher shear stress exceed the yield stress and remobilize the stored material. Experimental results show that on the steep slope, the mixture generates unsteady roll waves. Once these waves reach the gentle slope, they further amplify and evolve into distinct surge fronts, confirming the proposed model. These findings establish a conceptual framework for understanding the accelerated evolution of debris-flow surges.

How to cite: Song, D. and Liu, Y.: Debris Flow Surges Amplification Controlled by Topography and Rheology, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2920, https://doi.org/10.5194/egusphere-egu26-2920, 2026.

Extreme hydro-meteorological events are among the primary drivers of hydrologic and geomorphic hazards, posing an increasing threat to societies worldwide. The combined effects of climate change, and increased exposure and vulnerability in hazard-prone areas have led to a continuous rise in disaster risk.
This contribution addresses some key challenges in forecasting and managing hydro-meteorological processes across two main interrelated contexts—data-rich or data-scarce regions—which, despite their known differences, share common issues of scale, complexity, and uncertainty in hazard–society interactions.
In both environments, local-scale factors such as small-scale processes, and human disturbances interact with regional climate variability and large-scale atmospheric drivers to shape evolving hydro-geomorphic processes. At the same time, decisions happen at national, basin, or urban scales, often creating cross-scale mismatches between where hydro-meteorological processes materialize and where decisions are taken.
The presentation discusses how Earthcasting-oriented approaches, such as the integration of remote sensing, reanalysis products, crowd-sourced information, and qualitative socio-economic data, can partially address these gaps. While these data sources introduce new uncertainties, they also provide opportunities to improve awareness and support process-based forecasts and decision-making in regions where conventional data are unavailable, or they might not be enough.
Building on recent advances in technology but also risk science, this talk advocates for integrated assessment frameworks that explicitly account for cross-scale interactions, feedbacks, and data limitations, also highlighting implications for communication strategies. Ultimately, advancing such integrated approaches is essential for translating scientific knowledge into an added social value of the predictability of Earth surface processes.

How to cite: Sofia, G.: From Climate Data to Decisions in the Age of Extremes:  Challenges and Opportunities, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3013, https://doi.org/10.5194/egusphere-egu26-3013, 2026.

Understanding sediment grain size distribution in riverbeds is fundamental to analyses of sediment transport, riverbed morphology, and ecological habitats. Recent advances in unmanned aerial vehicle (UAV)–Structure-from-Motion (SfM) photogrammetry have enabled indirect characterization of sediment grain size (D) using surface roughness (R) derived from point cloud analyses. However, the relationships between grain size and roughness, as obtained using different roughness metrics in mountain rivers, remain insufficiently investigated.

In this study, manual sediment sampling and high-resolution UAV surveys were conducted across multiple mountainous river reaches in Taiwan, characterized by coarse bed materials and wide grain size distributions. SfM-derived point clouds were used to compute three roughness metrics: roughness height (RH), standard deviation of elevations (σ), and detrended standard deviation (σd). Linear relationships were established between local grain sizes (Di, where i = 16, 25, 50, 75, and 84) and their corresponding percentile roughness values (Ri). In addition, integrated power-law relationships were developed by pooling all paired Di–Ri data across the study reaches.

The results indicate that all three roughness metrics (RH, σ, and σd) exhibit strong correlations with grain size in gravel-bed rivers when analyses are conducted within the same river reach. The linear Di–Ri relationships show moderate to strong correlations (R² = 0.57–0.95), with the D₅₀–R₅₀ relationship demonstrating the highest consistency across all three metrics. Similarly, the integrated power-law relationships derived from the three roughness metrics yield high correlations (R² = 0.89–0.93). However, notable differences emerge when these relationships are applied to other river reaches. The RH-based relationship maintains more consistent predictive performance, whereas relationships derived from σ and σ_d exhibit larger deviations. These results suggest that RH-based roughness metrics offer superior applicability for estimating sediment grain size in mountain rivers. Overall, this study provides practical insights into the selection of suitable roughness metrics for grain size estimation in coarse-grained riverbeds.

How to cite: Lai, T. Y., Jan, C. D., Lai, K. C., and Hsu, Y. C.: An Evaluation of Riverbed Roughness Metrics Derived from UAV–SfM Point Clouds and Their Relationships with Grain Size Distribution in Mountain Rivers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4395, https://doi.org/10.5194/egusphere-egu26-4395, 2026.

To effectively assess the growing hazard related to debris flows, it is crucial to simulate these natural
grain-fluid flows at a reasonable computational cost. To complement existing depth-averaged grain-fluid flow
models with an upper-fluid layer, we propose here a model with an upper-solid layer, as a first step towards the
development of unified models describing all possible configurations. This model accounts for granular mass
dilatancy and pore fluid pressure feedback and solves for solid and fluid velocity in the mixture and for the
upper-solid velocity. Simulation in uniform configurations reveals the rich behaviour of the flow and shows that
the upper-solid and upper-fluid models may predict very different behaviour. Our work highlights the need of
developing two-layer models accounting for dilatancy and unifying upper-solid and upper-fluid configurations
in the same framework.

How to cite: Mangeney, A., Bouchut, F., Fernandez-Nieto, E., and Narbona-Reina, G.: A depth-averaged grain-fluid model with dilatancy and an upper-solid layer, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5017, https://doi.org/10.5194/egusphere-egu26-5017, 2026.

Bedload transport is ubiquitous in natural environments and encompasses flow regimes from saltation to sheet-flow, characterized by distinct fluid–particle interaction mechanisms. Accurately capturing these processes requires a numerical approach that can capture both turbulence and fluid-particle interactions, for which challenges exist due to the constraints of grid resolution on the coupling accuracy. In this study, we propose a semi-resolved LES–DEM framework to overcome such limitations in the conventional CFD-DEM paradigm. A feedback-controlled body-force term is also proposed to maintain a prescribed discharge under periodic boundary conditions in turbulent open-channel flow simulations. Three benchmark cases are conducted to assess the accuracy and robustness of the proposed framework, including clear-water turbulent channel flow as well as bedload transport in both saltation and sheet-flow regimes. The present method is demonstrated to effectively overcome the conventional grid-size limitation and thus allows the fluid field to be resolved on sufficiently fine grids while preserving accurate fluid-particle coupling. We further investigate the micromechanical processes underlying the transition from the saltation to sheet-flow regimes and quantify the thickness of the transport layers as functions of the Shields number. Overall, this framework provides a unified and reliable numerical tool for simulating sediment transport across a broad range of flow regimes, offering a solid basis for micromechanical analysis and the development of continuum models.

How to cite: Liu, Y., Jing, L., Wu, Z., and Fu, X.: Semi-resolved LES–DEM simulations of turbulent bedload transport from saltation to sheet flow regimes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5469, https://doi.org/10.5194/egusphere-egu26-5469, 2026.

Particle-size segregation is a common phenomenon in granular materials that has attracted increasing attention in recent years. Yet segregation under recirculation remains underexplored compared to segregation in simple-sheared gravity-driven flows. In this study, we investigated the dynamics of a bi-dispersed granular mixture flowing over an inclined conveyor belt. This belt pulled particles upstream, creating a recirculating flow. We visualized the internal structure of granular flow in a vertical plane by matching the refractive indices of the fluid and particles, and then located the particles. We observed an upstream accumulation of small particles and downstream accumulation of large particles, these two regions being separated by a curved interface. We think that this separation resulted from the interplay between particle recirculation and segregation: 1) surface particles moved downstream while bottom particles moved upstream; 2) segregation led to particles separating during recirculation, with full separation achieved at the channel ends. We developed a depth-averaged advection-diffusion equation to quantify this phenomenon by treating the recirculation as convection. This study provides new insights into the coupled mechanisms of recirculation and segregation in granular materials.

How to cite: Chen, Y. and Ancey, C.: Size segregation of granular mixtures under recirculation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7103, https://doi.org/10.5194/egusphere-egu26-7103, 2026.

The Var River in southeastern France represents an example of a Mediterranean fluvial system profoundly modified by human activity. Over the past eight decades, engineering works, gravel mining, and urbanization have progressively confined and simplified the channel, while the river remains a vital water resource for the city of Nice and its surroundings.

We present a multi-temporal and multi-scale analysis of the lower Var River’s morphological evolution between 1940 and 2025. Historical aerial and satellite images (n > 50) were analyzed to quantify changes in braided index, channel confinement ratio, slope–width relationships, and channel morphology classes. A high-resolution UAV survey conducted in 2025 covered 20 km of the lower valley, producing detailed orthomosaics and digital elevation models from over 80,000 images. Additional sedimentological analyses combining terrestrial photogrammetry and laboratory measurements thoroughfully characterized grain size and lithology of fluvial landforms.

Results reveal a complex spatial pattern in channel form: the lower Var alternates between multi-thread and single-thread morphologies along its 20 km course, with transitions occurring over distances of less than one km. These abrupt shifts are linked to local confinement, engineered structures (among which weirs which underwent recent lowering), and bedload disconnection. Overall, the river has undergone strong simplification and narrowing, with active-channel reductions exceeding 60% in channelized reaches. The present morphology reflects a hybrid, fluvial state shaped by human regulation and contrasted hydrology. These findings provide new insights into the geomorphic resilience of Mediterranean rivers and inform sediment management and corridor planning for the Nice Metropolitan region, since it present the first high-resolution analysis of this fluvial corridor.

How to cite: Granados-Bolaños, S., Picourlat, F., Ouassanouan, Y., Billaud, F., Chapuis, M., and Abily, M.: Fluvial geomorphology and historical evolution of the Var River, France: a case study of a highly anthropic Mediterranean braided channel, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7135, https://doi.org/10.5194/egusphere-egu26-7135, 2026.

Granular sediments in rivers, coasts, and pipelines often undergo particle size segregation due to the action of the carrier fluid and particle-particle interactions. This process can significantly affect geomorphology and the associated geohazards, but our mechanistic understanding of granular segregation in fluid-driven bedload transport remains elusive. In this study, a particle-scale numerical simulation based on the coupled computational fluid dynamics–discrete element method (CFD-DEM) is conducted to investigate the segregation of a bidisperse bed sheared by high-viscosity fluids. The evolution of segregation under varying shear intensities, characterized by the Shields number, is systematically analyzed in laminar flow. The results show that: (1) under various Shields numbers, the granular bed can be divided into an upper bedload layer (fluid-like, fast-moving) and a lower creep layer (solid-like, slowly moving), with the bedload layer thickening and the creep layer thinning linearly as the shear intensity increases; (2) particle segregation evolves exponentially over time, and at the same duration, the final degree of segregation for the entire bed increases linearly with the Shields number; (3) the segregation timescale shows a non-monotonic dependence on the Shields number, governed by the competing effects of increasing segregation velocity and active layer thickness as the Shields number is increased; and (4) the segregation timescale follows a power-law relationship with the shear rate in laminar flow, showing similarities to dry granular flow behavior. Future work will focus on developing a predictive model that captures the evolution of coarse and fine particle concentration profiles, thereby enhancing our modeling capabilities of granular segregation and its feedback effects on the mobility of sediment transport.

How to cite: Li, X. and Jing, L.: Size Segregation of Bidisperse Granular Beds in Laminar Shear Flow: A CFD-DEM Investigation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8573, https://doi.org/10.5194/egusphere-egu26-8573, 2026.

Debris flows are a major natural hazard in mountainous regions worldwide and significantly impact the sediment budgets in alpine areas. However, the development of debris flow frequency under climate change conditions has not yet been conclusively clarified, as long-term, comprehensive event records (i.e. not biased towards large events) are scarce. As alpine debris flows are predominantly triggered by high-intensity and short-duration rainfall events, precipitation records can be useful for inferring potential triggers, particularly under transport-limited conditions. As high-resolution precipitation measurements are rarely available over long periods of time, we employed dynamical downscaling of a Regional Climate Model (RCM) based on the Advanced Weather Research and Forecasting model (WRF). This approach resulted in a high-resolution climate model dataset covering most of the Central Alps, with a spatial resolution of 2x2 km and a temporal resolution of 15 minutes. This model enabled us to analyse high-intensity, short-duration rainfall events since the end of the Little Ice Age in 1850.

We compared the RCM with a debris flow record in the Horlachtal catchment in Tyrol, Austria. By analysing remote sensing datasets such as historical and recent aerial imagery, airborne lidar data and lichenometric dates, we identified 991 individual debris flows in the area between 1947 and 2022. Combining the observation dataset with the RCM rainfall data enabled us to take an integrated approach to assessing changes in debris flow frequency in the Horlachtal and their climatic drivers since 1850. The results provide insights into possible future trends in debris flow frequency in a changing climate, showing a weak positive long-term trend for the Horlachtal. The RCM's coverage allows for similar studies in other Alpine regions, offering more detailed insights into the spatial variability of changes in debris flow activity within the Central Alps.

How to cite: Rom, J., Pfeiffer, M., Marzeion, B., Heckmann, T., Haas, F., and Becht, M.: Evaluation of a downscaled Regional Climate Model for analysing the frequency of debris flows since 1850, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9692, https://doi.org/10.5194/egusphere-egu26-9692, 2026.

Landslide Dam-Break Outburst Floods (LDBOF) are devastating natural hazards that drastically reshape downstream river morphologies. However, their inaccessibility, high risk of equipment loss, and sparse field data collection severely hinder hazard understanding and timely warning capabilities. The 2000 Yigong LDBOF event in China is one of the most significant modern recorded cases, yet it suffers from limited observational data. To address this gap, we integrated multi-source data—including open-source elevation datasets, literature-derived records, satellite-based flood inundation extents, and direct field observations—to develop a comprehensive input dataset for hydro-morphodynamic modeling of the event. Model validation against field observations and comparable studies confirmed the reasonableness of simulated lake emptying, dam breaching, flood inundation, bank erosion, and channel infilling processes. Our results reveal key morphodynamic characteristics of the Yigong LDBOF: dam material transport was dominated by translational motion during the flood rising stage and dispersive transport during the falling stage. The outburst flood peak discharge reached ~60 times that of typical meteorological floods, significantly amplifying the effects of river width on dam material transport. We further proposed a sediment transport equation that incorporates the regulatory effect of large boulders. Post-event channel recovery simulations, validated with remote sensing data, indicated minimal planform changes, with bed incision driven by headward erosion as the dominant morphological adjustment. Large boulders acted as a stabilizing factor, limiting upstream erosion and forming sediment supply-limited reaches. This study provides a robust multi-source data integration and modeling framework for LDBOF events with sparse observations, offers new insights into cross-scale hydro-morphodynamic processes of extreme floods, and the proposed sediment transport equation improves the accuracy of simulating boulder-influenced sediment dynamics—supporting hazard risk assessment and downstream river management for future LDBOF events.

How to cite: Lei, Y., Hassan, M., Rosatti, G., Fraccarollo, L., Zugliani, D., Fu, X., and Shi, H.: Morphodynamic responses to the 2000 Yigong dam-break flood: Insights from back-analysis and cross-scale modelling challenges, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9737, https://doi.org/10.5194/egusphere-egu26-9737, 2026.

How to cite: Gailleton, B., Steer, P., Cordonnier, G., and Clubb, F.: Efficient Hydrodynamic Modeling at the Landscape Scale: Quantifying River Width and Shear Stress Variability to Decode Tectonic Signals, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11152, https://doi.org/10.5194/egusphere-egu26-11152, 2026.

Coherent, energetic airflow structures control the incipient aeolian entrainment of coarse sediment and plastic debris, but their effect is poorly captured by classical, time-averaged shear-stress thresholds. This contribution showcases the results from recently published work [1, 2] that combines a particle-scale energy framework with wind-tunnel observations to quantify how individual sweeps and related structures trigger rocking, creep and full rolling, thereby regulating geomorphic work and debris mobility at Earth’s surface.

Wind-tunnel experiments were conducted in a 30 m environmental facility over a fixed rough bed of identical 40 mm celluloid spheres, representing idealized gravel and light plastic debris under fully turbulent, near-threshold flow (U ≈ 7.5–8.2 m s⁻¹). Synchronous 1 kHz measurements of near-bed airflow (2D hot-film) and particle displacement (0.1 mm laser distance sensor) resolve intermittent rocking and episodic rolling of a single exposed particle on a regular bed, under an atmospheric boundary layer with logarithmic mean profile and near-surface turbulence intensities up to ~20%.

A micromechanical model defines “energetic airflow events” as intervals where instantaneous drag exceeds an initial resistance level and persists for a finite duration, and relates their energy content Ef ∝ ∫u³dt to the minimum mechanical work F_g z_cr required to push a particle over its micro-topographic barrier. The resulting work-based criterion C_eff∫u³dt ≥ const introduces a normalized efficiency C_eff, estimated from the ratio of drag work ∫u²vdt to event energy, which partitions motion regimes from creep through rocking to incipient rolling and near-saltation. Quadrant analysis of uw shows that >85% of both rocking and rolling events are associated with Q4 sweeps; a simple peak-force condition u²_f,p ≥ u²_cr,0 is necessary for motion but insufficient for full entrainment, whereas the energy criterion correctly classifies ≈90–95% of observed rocking vs. rolling events. These results provide a transferable, event-based description of how coherent turbulent structures drive low-mobility aeolian transport, including mechanical sieving on gravel-mantled megaripples and the mobilisation of meso- to micro-plastic debris.

References

[1] Valyrakis, M., Zhao, X., Pähtz, T., & Li, Z. (2025). The role of energetic flow structures on the aeolian transport of sediment and plastic debris. Acta Mechanica Sinica, 41(1), 324467. https://doi.org/10.1007/s10409-024-24467-x.
[2] Zhao, X. H., Valyrakis, M., Pähtz, T., & Li, Z. S. (2024). The role of coherent airflow structures on the incipient aeolian entrainment of coarse particles. Journal of Geophysical Research: Earth Surface, 129(5), e2023JF007420. https://doi.org/10.1029/2023JF007420.

How to cite: Valyrakis, M., Pähtz, T., and Zhao, X.: From sweeps to sieving: a particle scale work-based criterion for intermittent aeolian entrainment of gravel and plastics under coherent turbulent structures, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11556, https://doi.org/10.5194/egusphere-egu26-11556, 2026.

The incipient motion of coarse particles critically governs bed stability, sediment transport dynamics, and geomorphic evolution in turbulent flows, with profound implications for riverbed destabilization, flood risk, and the integrity of hydraulic infrastructure. Despite extensive research, the ways under which microtopographic pocket arrangements—clusters or depressions formed by particle packing— modulate entrainment thresholds remains relatively underexplored. 
This presentation aims to outline the effects of varied pocket configurations on the critical hydraulic conditions required for particle entrainment under turbulent flow fields. Utilizing instrumented particles equipped with inertial measurement units (IMUs) [1, 2] to record high-fidelity particle accelerations and angular velocities, we probe both particle kinematics and dynamics, at the onset of motion. Novel flow-particle interaction metrics, derived from these measurements, reveal the underlying physical mechanisms—such as torque imbalances and lift generation—that drive or resist entrainment.
We hypothesize that subtle differences in pocket geometry and orientation can substantially elevate or lower the entrainment threshold, necessitating distinct flow field characteristics (e.g., shear stress and turbulence intensity) for motion initiation [3, 4]. Preliminary results from controlled flume experiments demonstrate threshold shifts across configurations, underscoring the sensitivity of bed stability to local topography. 
These insights aim to highlight the transformative potential of IMU-based instrumentation for real-time risk assessment of riverbed and bank destabilization in natural streams, as well as scour development in engineered channels, for sustainable river management and infrastructure resilience.
 
References
1. Al-Obaidi K, Xu Y, Valyrakis M. The design and calibration of instrumented particles for assessing water infrastructure hazards. J Sens Actuator Netw. 2020;9(3):36. doi:10.3390/jsan9030036.
2. Al-Obaidi K, Valyrakis M. A sensory instrumented particle for environmental monitoring applications: development and calibration. IEEE Sens J. 2021;21(8):10153-10166. doi:10.1109/JSEN.2021.3053080.
3. Al-Obaidi K, Valyrakis M. Linking the explicit probability of entrainment of instrumented particles to flow hydrodynamics. Earth Surf Process Landf. 2021;46(12):2448-2465. doi:10.1002/esp.5178.
4. Al-Obaidi K, Valyrakis M. Coherent flow structures linked to the impulse criterion for incipient motion of coarse sediment. Appl Sci (Basel). 2023;13(19):10656. doi:10.3390/app131910656.

How to cite: Papadaki, A. and Valyrakis, M.:  Influence of Pocket Geometry on the Incipient Entrainment of Coarse Particles in Turbulent Flows , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11632, https://doi.org/10.5194/egusphere-egu26-11632, 2026.

Understanding the impact of geophysical flows on the channel bed is essential for assessing erosion processes of bed material. In this study, the discrete element method (DEM) is used to simulate idealized, steady-state, fully-developed granular flows impacting the channel bed with systematically varying total particle number (1000-30000), grain size (2-16mm), and slope angle (28-34°) to investigate the probability distributions of the basal force. The probability density functions of the basal force, normalized to the mean force, were calculated and fitted with ten probability distributions. Four indices, namely R², Residual Sum of Squares (RSS), Wasserstein distance, and information entropy, are introduced to evaluate the goodness of fit for each probability density distribution. By comparison, the broad probability density distribution of normalized basal force can be well-described by Gamma distributions (GD) with its shape and scale parameters. The shape parameter of the Gamma distribution is positively correlated with the total particle number and grain size, but negatively correlated with the slope angle. An opposite relationship is revealed in the scale parameter of the Gamma distribution. Additionally, we analyzed flow kinematics by calculating the coordination number, dimensionless velocity, shear rate, inertial number, and volume fraction, and linking these variables to the shape and scale parameters. The coordination number, shear rate, inertial number, and volume fraction serve as effective proxies for the shape and scale parameters, enabling interpretation of the statistical characteristics of monitored basal forces in geophysical mass flows.

How to cite: Tang, H., Fang, J., Cui, Y., Turowski, J., Jing, L., and Kong, Y.: Basal force distribution from steady fully-developed granular flows, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12336, https://doi.org/10.5194/egusphere-egu26-12336, 2026.

The central challenge in understanding extreme hydro-geomorphologic events is the persistent lack of integrated, quantitative observations capable of developing and constraining predictive models. While flash floods and associated sediment transport represent an escalating hazard under climate change, their underlying dynamics remain poorly understood across the spatio-temporal scales required for effective risk mitigation. Existing monitoring is often fragmented, with upcoming novel approaches only partly resolving key unknowns when used in isolation. For instance, optical methods such as UAV-based photogrammetry and camera gauges provide high resolution surface process data but cannot resolve subsurface bedload dynamics, whereas environmental seismic methods capture particle-riverbed interactions and signatures of turbulence but produce indirect, composite signals that are difficult to isolate and quantify.

To bridge this gap, we envision a multi-modal approach that moves beyond those single-technique or single-sensor proxies. To reliably and robustly observe temporarily evolving interlinked key parameters, i.e., water level, flow velocity, and hydraulic geometry, major steps involve using stereo-vision for precise scaling and channel cross-section updates, alongside AI-based optical flow for complex velocity fields. By integrating low-cost, event-triggered sensors (e.g., thermal & multispectral cameras, seismometers, and LiDAR), we can automate the retrieval of discharge as well as additional parameters such as turbidity and granulometry. Using photogrammetric change detection and AI-driven image processing we can further bridge terrestrial and aerial perspectives (e.g., from UAV), moving toward a physically consistent characterization of extreme events. By integrating high-resolution 3D imaging and seismic data inversion, it becomes possible to capture water and sediment dynamics simultaneously, resulting in unique complementary information on the same event.

In this framework, laboratory experiments provide the necessary controlled conditions to infer the capabilities, caveats and calibration measures for this sensor integration. Highly resolved computational fluid dynamics multiphase flow modelling will generate synthetic reference datasets to disentangle environmental signals and sensor noise. These heterogeneous data streams are integrated via AI-based fusion and uncertainty modelling to resolve non-linear relationships governing coupled water–sediment dynamics. Ultimately, hydrological and hydraulic modelling serves as a testbed for upscaling, in which models are informed by improved process knowledge-based observation data and its uncertainty to evaluate how small-scale insights alter catchment-scale predictions.

From this framework, significant gaps emerge that define the current research frontier. A critical unresolved challenge is the systematic separation of source terms from the superimposed signals generated by the actively evolving sediment-carrying river during flood events. Furthermore, the transition from "data-rich" local observations to “data-poor” but "process-informed" regional models is still hindered by the lack of scalable frameworks that can maintain physical consistency across different scales, i.e., climatic and geomorphological regimes. Addressing these gaps requires a coordinated shift from observing isolated parameters to an integrative, physics-based monitoring loop that can provide truly scalable, model-ready information for extreme events.

How to cite: Eltner, A., Dietze, M., Kowalski, J., Aberle, J., Grundmann, J., and Vowinckel, B.: Multi-Modal Monitoring and Modelling of Extreme Hydro-Geomorphological Events: Bridging the Gap Between Local Dynamics and Catchment-Scale Predictions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12572, https://doi.org/10.5194/egusphere-egu26-12572, 2026.

Dense sedimentary flows underpin a wide range of geomorphic processes, from bedload transport in rivers to debris-laden shallow flows, yet their rheological description across regimes remains incomplete. In particular, the transition from viscous-dominated to inertia-dominated behavior in dense suspensions poses a central challenge for constitutive modeling of subaqueous sediment transport. Here, we present a unified numerical investigation of the viscous–inertial transition in sheared sedimentary flows using particle-resolved Direct Numerical Simulations (pr-DNS), spanning idealized rheometric configurations and flow-driven sediment beds.

We employ both pressure-imposed and volume-imposed rheological frameworks to systematically probe the role of fluid viscosity, shear rate, granular pressure, particle friction, confinement, and boundary roughness. Across configurations, we characterize rheology in terms of the macroscopic friction and solid volume fraction expressed as functions of combined viscous and inertial control parameters. Our results confirm that the transition can be described by an additive scaling of visco-inertial stresses but reveal that different rheological quantities respond differently to inertia.

In pressure-imposed simulations of dense frictional suspensions, we find that the viscous–inertial transition occurs at Stokes numbers ranging from 5 to around 8, consistent with recent experiments. Notably, shear stress exhibits a more gradual transition than particle pressure, indicating a decoupling of stress components. Microstructural analysis shows that this behavior arises from the combined action of lubrication and tangential contact forces, as particles progressively shift from rolling to sliding contacts. This shift is governed not only by the Stokes number, but also by proximity to jamming and inter-particle friction.

Complementary volume-imposed simulations between rough confining walls demonstrate that boundary conditions strongly influence the measured rheology through particle layering and inter-layer mixing. Wall roughness and cell height modulate stress levels and effective friction, including weakening of the macroscopic friction during the transition, while preserving a consistent viscous–inertial scaling across cases. Despite a reduction in contact number, increased force magnitudes on remaining contacts drive the inertial regime.

Finally, simulations of pressure-driven shallow flows over sediment beds show that the transition occurs at Stokes numbers comparable to those of our numerical and experimental results of pressure-imposed rheometry, with distinct scaling coefficients for volume fraction and macroscopic friction. Together, these results highlight the complex, multi-scale nature of sediment rheology and underscore the need for refined constitutive laws that explicitly account for microstructure, confinement, and stress anisotropy in geomorphic sediment transport.

How to cite: Vowinckel, B., Khodabakhshi, A., Konidena, S., and Tapia, F.: Rheology of sedimentary flows across the viscous–inertial transition, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12701, https://doi.org/10.5194/egusphere-egu26-12701, 2026.

The prediction of bedload sediment transport remains challenging due to the multi-scale interactions that link grain-scale dynamics, bed morphology, and turbulence. Grain-scale processes are influenced by particle shape and contribute to the spread in existing bedload models. Experimental access to these processes is limited, making numerical simulations a valuable complementary tool. Most numerical studies to date represent sediment grains as spheres to reduce computational cost or intentionally exclude shape effects. More recent work has demonstrated the importance of shape using ellipsoidal approximations which capture the overall grain form but loose finer surface irregularities. Only a few simulations have employed more realistic clumped-sphere grain approximations and have shown that grain shape introduces significant uncertainty in entrainment and transport predictions.

This contribution advances the quantification of grain-shape effects by using realistic representations of grain geometry obtained from measurements in the literature. It presents direct numerical simulations of turbulent bedload transport with low particle loading in a highly mobile regime using fully resolved, realistic sand grains. Three simulations with monodisperse but polymorph particles are considered, such that only grain shape is varied. One configuration represents smooth, well-rounded sand grains, the second consists of more angular and irregular grains. A third simulation with uniform spheres serves as a reference. The realistic grain samples are generated statistically following an established methodology that yields two distinct sand populations. The grains in these populations are characterized using sphericity and roundness and are classified using the Zingg diagram. Although the Zingg-class of all grains is spheroid, the grain populations can be subdivided based on the distributions of the other two shape descriptors, with sphericity capturing larger-scale morphology and roundness reflecting smaller-scale surface irregularities.

Across the three simulations, the Shields parameter increases with increasing grain irregularity. Furthermore, the particle ensembles in all simulations show oscillatory dynamics during statistically steady bedload transport, attributed to the recurring formation of particle clusters, with the characteristic period increasing with grain irregularity. Shape-conditioned statistics obtained through double averaging show that in the case of the angular grain population more rounded grains accumulate near the channel bottom, while more angular grains are transported to higher elevations. This sorting is not observed for the well-rounded grain population. Additionally, for both grain populations, the rotational energy of the grains increases with irregularity, although rotation remains overall weak compared to translational motion in the present highly mobile regime.

How to cite: Rebel, R. and Fröhlich, J.: Resolved DNS of bedload transport with realistic grain morphology, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13379, https://doi.org/10.5194/egusphere-egu26-13379, 2026.

Granular media is observed in a variety of natural contexts. Whether they come in the form of landslides, debris flows, pyroclastic density currents, bed load, fault gouge, or magmatic crystals, they can fail catastrophically and jam. Here we introduce a characterisation that examines collective motion within granular systems to probe their stability as they are pushed towards the point of failure and stoppage. Using particle-resolved simulations, we show that this characterisation gives early indication of weakening prior to external measures. This characterisation is agnostic to the method of destabilisation, whether it be from increasing slope angles or fluid injection. Applying this characterisation to analogue experiments shows that it can easily demarcate between a static deposit, agitated particles, and an actively destabilizing layer, showing promise in using remote signals to probe the stability of natural systems.

How to cite: Zrelak, P., Breard, E., Makris, S., and Dufek, J.: The Edge of Stability: From Collective Vibrations to Jamming and Failure in Granular Media, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15476, https://doi.org/10.5194/egusphere-egu26-15476, 2026.

Braided rivers are dynamic systems that support diverse habitats associated with their shifting mosaic of anabranches, backwaters, bars and islands. These units are characterized by chaotic, but not random, distributions of substrate, elevation and hydraulics at multiple scales. Modelling sediment supply or flow-driven changes in riverbed composition is notoriously difficult given the inherent dynamism and multiple scales defining large braided rivers.

In this research, we present a new data-rich modelling framework which combines census-scale [1 m] substrate classification with detailed 2D hydraulic models. The resulting transport capacity estimates can, for a static bed, be quickly applied to any transient flow scenario while retaining spatial detail. We then use the information gathered during the 2D modelling to parameterise a 1.5-dimensional transport solution in the time-evolving CASCADE sediment routing framework.

The 2D model uses a substrate map of a 56-km reach of the Rangitata [Rakitata] River, Aotearoa New Zealand, derived by machine learning based on high-fidelity helicopter lidar and orthophotography. A library of 2D steady-state hydraulic models is then run over the substrate map to predict the spatial and temporal capacity for sediment transport.

The adapted 1.5D-CASCADE model captures a defining feature of braided rivers, width variability, with a reach-specific hypsometric solver, tested against the 2D results, that predicts flow and sediment transport. The half-dimension is width, discretised against height using the 2D predictions of inundation and active area. The 1.5D model can then evolve bed composition both laterally across the braidplain and longitudinally down the river, within hydraulic geometry set by the template survey, including storage and remobilisation in side channels and floodplains.

The models are tested and applied to simulate the effects of flow regulation on bed composition in the Rangitata River. The model’s longitudinal consistency was only possible when using the spatial substrate data, and predictions are corroborated by lidar change detection. Results demonstrate that subtle changes in flow regime can alter where sediment is stored across the braidplain, with sedimentation impacts focused on side channels. Transfer of the model to other rivers indicates that width-varying solvers produce more stable sediment routing predictions than any single width, while remaining computationally efficient. 

How to cite: Rogers, J. and Brasington, J.: Adapting CASCADE for braided rivers: A 1.5D sediment transport approach with variable substrate and width, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15789, https://doi.org/10.5194/egusphere-egu26-15789, 2026.

In foreland basins adjacent to collisional mountain belts, rivers exhibit an abrupt gravel-sand transition (GST) at ~10-40 km downstream of mountain fronts, where surface median grain size reduces from ~10 mm to ~1 mm. This is the only abrupt downstream reduction in grain size in fluvial systems. Existing theories attribute GST formation to size-selective transport of bimodal sediment, rapid deposition of sand from the washload, and gravel exhaustion. These mechanisms predict that GST location should respond systematically to changes in hydraulic conditions (channel gradient, flow strength), sediment supply (gravel flux), and accommodation space (subsidence rate). However, observations from the Himalayan foreland basin reveal significant along-strike variability in GST locations despite similar gravel lithology, comparable subsidence rates, and uniform climatic forcing. This unexplained spatial variability indicates that additional controls on GST formation remain poorly understood.

Here, we hypothesize that particle shape—an intrinsic sediment property traditionally considered secondary to grain size—exerts first-order control on GST location through its influence on gravel mobility. To test this hypothesis, we developed a force-balance framework accounting for drag, lift, and rotational forces to model gravel transport as a function of particle shape. Experiments with varying bed matrix characteristics demonstrate that gravel mobility is strongly modulated by shape variations under identical hydraulic conditions. Field measurements of particle shape distributions from Himalayan foreland rivers reveal that GST locations coincide spatially with downstream increases in the proportion of low-mobility shapes (equant and platy forms). Progressive accumulation of these less mobile shapes reduces the bulk mobility of the gravel bedload, causing the gravel front to stall.

Our results demonstrate that particle shape exerts first-order control on GST formation and location, operating independently of climate and tectonic forcing. This intrinsic control has likely influenced sediment routing in both ancient and modern foreland basins worldwide. The findings suggest that GST positions in stratigraphic records reflect the evolution of particle shape rather than solely changes in external forcing. Understanding this shape-controlled mechanism is essential for interpreting sedimentary archives, predicting downstream sediment delivery, and refining landscape evolution models in mountain-foreland systems.

How to cite: Panda, S. K., Kundu, S., Mandal, S. K., and Scherler, D.: Shape Matters: How particle morphology affects the location ofthe Gravel-Sand Transition., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16255, https://doi.org/10.5194/egusphere-egu26-16255, 2026.

The study-to-study variability of bedload flux measurements in turbulent sediment transport borders an order of magnitude, even for idealized laboratory conditions. This uncertainty stems from physically poorly supported, empirical methods to account for channel geometry effects in the determination of the transport-driving bed shear stress and from study-to-study grain shape variations. Here, we derive a universal procedure of bed shear stress determination. It consists of a physically-based definition of the bed surface and a channel sidewall correction that does largely not rely on empirical elements, except for well-established scaling coefficients associated with Kolmogorov's theory of turbulence. Application of this procedure to bedload transport of spherical grains---to rule out grain shape effects---collapses data from existing laboratory measurements and grain-resolved CFD-DEM simulations for various channel geometries onto a single curve. By contrast, classical sidewall corrections, such as the Einstein-Johnson method, as well as an alternative bed surface definition, are unable to universally capture these data, especially those from shallow or very narrow channel flows. The sidewall correction method is also independently supported by data from systematic experiments of open-channel flows over fixed rough beds with various width-to-depth ratios.

How to cite: Pähtz, T., Chen, Y., Yu, H., Wei, M., and Duran, O.: Bed shear stress in bedload transport: new methods of sidewall correction and bed surface determination, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16411, https://doi.org/10.5194/egusphere-egu26-16411, 2026.

Vertical velocity profiles in erosive multiphase mass flows control how momentum is transferred from a moving landslide to the underlying bed and therefore govern erosion, entrainment, and mass enhancement. Although erosion is known to increase landslide mobility, the particle-scale mechanisms by which internal shear drives sediment mobilisation remain poorly constrained. In particular, the vertical distribution of velocity in erosive granular flows is largely unknown, despite providing the critical link between flow dynamics and bed response. Field measurements document a wide range of velocity profile shapes but lack the spatial resolution required to quantify shear close to the bed. By contrast, previous laboratory studies either failed to resolve internal kinematics under erosive conditions or relied on artificial, rounded particles that suppress the frictional interactions characteristic of natural sediments. Consequently, differences between landslide velocity and the velocity of the eroded bed, as well as the vertical shear rates underpinning erosion-entrainment-mobility formulations, remain largely unconstrained by empirical data.

Here we present a new experimental dataset that directly addresses this gap. We conducted controlled laboratory experiments on landslide-like granular flows moving over an erodible bed composed of naturally crushed sand-gravel mixtures. A measurement approach based on Particle Image Velocimetry combines lateral imaging with plan-view observations, allowing continuous vertical velocity profiles to be reconstructed across the full flow depth during active erosion and entrainment. The experiments include dry granular flows and flows with varying water content, two representative grain-size classes, and systematic comparisons between erosive runs and reference cases over a rigid bed.

The results show that both the inertia of the erodible material and the time-dependent erosion rate fundamentally alter the vertical velocity profile. The velocity of the moving landslide and that of the erodible bed can now be clearly distinguished, enabling direct calculation of entrainment velocity and erosion drift. Shear mainly occurs near the bed-flow interface, evolving dynamically as material is entrained and creating velocity gradients that cannot be captured by depth-averaged approximations. These measurements provide the first quantitative characterisation of vertical shear under fully erosive conditions using realistic sediment properties. By resolving particle-scale velocity gradients, this study establishes the experimental basis required to calibrate and verify erosion-mobility models that explicitly depend on shear-rate-controlled entrainment, thereby advancing the predictive modelling of erosive landslides.

How to cite: Baselt, I., Krautblatter, M., Pudasaini, S., and Wetterauer, K.: Vertical Velocity Profiles in Erosive Landslides, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16480, https://doi.org/10.5194/egusphere-egu26-16480, 2026.

Fluvial dynamics hinge on sediment erosion, transport, and deposition. These are the forcing factors responsible for changing channel morphology and landform evolution. Our study analyses these processes at the confluence of the Damodar River and the Barakar River in eastern India. It is a transitional zone between Archaean-Proterozoic crystalline rocks, lower Gondwana formations, and Quaternary alluvium. The landscape remains in a constant state of change, shaped by the annual pulse of flood and profoundly altered by two hundred years of anthropogenic activity.

An integrated framework evaluates boundary conditions, morphologic responses, fluvial drivers, and terrace archives. Despite comparable flow velocities in active channels, rivers transport distinct grain sizes and lithologies. The right-bank remnants of the Damodar River evidence past high-energy regimes and are absent on the left bank. Terrace sequences are unpaired, sedimentologic units are unmatched, and bank structures preserve ancient high-velocity signatures.

How to cite: Kundu, S., Sinha, S., and Haque, S. M.: Geomorphic and sedimentary records for deciphering the landform evolution at the Damodar and Barakar River confluence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16521, https://doi.org/10.5194/egusphere-egu26-16521, 2026.

Coupled interactions between climate, vegetation, and geomorphic processes control sediment export from rapidly eroding badlands; however, their relative roles under future climate scenarios remain poorly constrained. We present a coupled landscape evolution model (LEM) and a dynamic vegetation model, CLIMBAD, applied to the Laval catchment (Draix-Bléone CZO, SE France) in a badland setting, to quantify how fluvial and hillslope erosion, together with frost weathering and vegetation dynamics, drive historical and projected sediment fluxes. The LEM is forced by temperatures (acting on frost weathering) and precipitation events, including depth, duration, and peak intensity. The dynamic vegetation model is calibrated to 1982-2021 vegetation maps and driven by topographic and climatic variables. Future climate (2022-2099) is generated using a stochastic weather generator calibrated on observations from historical data and future projections obtained from a regional climate model.

Model evaluation for 1985-2021 shows that coupling dynamic vegetation to the LEM improves agreement with observed annual sediment fluxes at the catchment outlet (i.e., R² increased from ~0.60 to ~0.66), demonstrating the importance of vegetation-erosion feedbacks. To isolate climatic controls, we ran four scenarios for future climate: (i) changing temperature (T) and precipitation (P), (ii) constant T with changing P, (iii) changing T with constant P, and (iv) constant T and P. These results help disentangle the relative contribution of a change in the precipitation regime and a change in temperature on sediment fluxes in a coupled system, with direct implications for sediment hazard assessment in climate‑sensitive badland landscapes.

How to cite: Sharma, H., Le Bouteiller, C., and Boulangeat, I.: Coupling Landscape Evolution and Dynamic Vegetation Models to Simulate Sediment Fluxes under Historical and Future Climate in the Laval Catchment (Draix-Bleone CZO, SE France), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19059, https://doi.org/10.5194/egusphere-egu26-19059, 2026.

Landscape evolution models typically solve three main processes: the conversion of rainfall to runoff, flow routing, erosion, and sediment transport, for a given precipitation time series, and a topographic surface. They can help to predict watershed dynamics in response to potential extreme events and anticipate potential damages. To that purpose, models must accurately represent the studied catchment and reproduce available observations, such as water discharge and sediment flux. This requires adjusting the model parameters representing the catchment characteristics, which can be challenging due to long simulation times, many uncertain characteristics and modeling errors.  

This study focuses on modeling the Pommeroye catchment — a 0.54 km² elementary watershed in the Canche River basin in northern France. The objective is to identify models able to reproduce the twenty extreme events identified in the data collected during the 2016-2017 hydrological year for discharge and suspended sediment at the catchment outlet. Topography is derived from a high-resolution (1m) LiDAR-derived digital elevation model. CAESAR-Lisflood is considered for dynamic simulation. The rainfall-to-runoff is modeled with a local storage term that has an exponential recession and is controlled by the water storage depth parameter “m”. From the generated surface runoff, the model continuously computes the flux of water and sediment across cells. Flow routing is solved via a reduced solution to the shallow water equations, where the friction term is computed via the Manning-Strickler model and hence controlled by the Manning’s roughness. Sediment transport follows the Wilcock and Crowe parameterization, with multiple controlling parameters. For the Pommeroye catchment, model run times are long, e.g. up to 24 hours on 36 CPUs, limiting the number of simulations that can be performed in practice. To overcome this, we developed a workflow combining machine learning-based surrogate models with sensitivity analysis and calibration. Gaussian processes are considered to mimic CAESAR-Lisflood from a limited training set and provide fast estimations of the simulator outputs for any input parameter values within given ranges. Instead of CAESAR-Lisflood, these predictions are used for variance-based sensitivity analysis (Sobol’ indices) and optimization (Efficient Global Optimization), drastically reducing the computation times.

A first sensitivity analysis highlighted that the m parameter mainly affects water discharge. However, no single m parameter value enables the model to correctly reproduce all data: the best fit is obtained with increasing values throughout the year, starting with low values in winter. In a second study, we thus added flexibility with time-dependent monthly values for m, leading to an improved match with water discharge data. Finally, the EGO approach - with fixed monthly m values - was considered to better reproduce suspended sediment data, identifying settling velocity and Manning’s roughness as key factors.

How to cite: uchasara huarachi, M. R., gervais, V., armitage, J., franke, C., and alary, C.: Surrogate-based sensitivity analysis and calibration for the hydro-sedimentary modeling of an elementary agricultural catchment, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19202, https://doi.org/10.5194/egusphere-egu26-19202, 2026.

Rainfall erosivity is a major driver of soil erosion and is highly sensitive to short-duration precipitation extremes, which are expected to intensify under climate change. Great advancement on climate data have been seen in the last decade, and convection-permitting climate models (CPMs) offer new opportunities to simulate rainfall characteristics relevant to erosivity. However, their performance in complex terrain remains insufficiently quantified.

We evaluate rainfall erosivity (RUSLE R-factor) simulated by a nine-member CPM ensemble from the CORDEX Flagship Pilot Study on Convective Phenomena over Europe, focusing on the Great Alpine Region. CPM estimates are compared with long-term, high-resolution rain-gauge observations from ~500 stations spanning a wide elevation range. We quantify and apply a temporal adjustment to reconcile hourly model output with 10-minute observations, then model performance vs observations is assessed for key erosivity-related variables, including rainfall intensity, event depth, frequency of erosive events, and mean annual erosivity. The CPM ensemble reproduces the spatial variability of rainfall erosivity with good skill and overall low bias, but exhibits clear elevation-dependent biases. Erosivity is underestimated at low elevations and increasingly overestimated at higher elevations, reflecting biases in rainfall intensity and/or event frequency. While low-elevation biases are largely consistent with sampling variability, high-elevation biases are predominantly systematic.

These results highlight the potential of CPMs for rainfall erosivity assessment and the importance of accounting for elevation-dependent biases in mountainous regions.

How to cite: Borga, M., Mansoor, A., Dallan, E., and Francesco, M.: Evaluation of convection-permitting models for rainfall erosivity in an Alpine region, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21488, https://doi.org/10.5194/egusphere-egu26-21488, 2026.

A numerical model is developed for the transport of mixed natural sediment and plastic particles, accounting for multiple size classes and material densities. The conceptual model drawn from a classico Hirano layered description. It includes a transport layer, an active layer and a substratum. In the transport layer mass conservation consists on fraction-wise Exner equations, including pickup and deposition rates, convective and diffusive transport in the transport layer, and local accumulation for each size and density class. Convective fluxes are the product of particle activity for each size and density classes (the conservative variables) and particle bulk velocity. The latter computed using a modified Luque and van Beek formulation, adapted to account for different sizes and particle densities. Thresholds for incipient motion are taken as calibration coefficients. A flux limiter is implemented to avoid over-saturation of the transport layer and to ensure positivity of particle activity. The pickup function is derived from probabilistic descriptions of sediment entrainment (taking into account density) and deposition rates are functions of actual particle activity and sedimentation velocity. The dynamics of the active layer is determined by empirical availability functions by size. The volume of the active layer is kept constant and scaling with the initial d90 of the mixture. Instantaneous mixing is assumed. As a consequence, during deposition the composition of the active is transferred to the substratum. During erosion, the composition of the substratum is incorporated in the active layer.

The model is calibrated with laboratory experiments conducted under steady and overfeeding flow conditions. Two flumes were employed. A 5.2 m long, 25 cm wide, and 35 cm deep flume was used to conduct flat-bed experiments in two scenarios: (i) homogeneous bed composed of plastic granules, and (ii) gravel or sand bed mixed with plastic granules, which were manually seeded at clastic bed surface for different covering percentage. A 12 m long, 40 cm wide channel was used to conduct gravel-sand sediment sorting experiments, leading to surface coarsening, and overfeeding experiments. Calibration consisted in finding best fits to threshold values of grain velocities, ensuring the observed equal mobility characteristics of poorly sediments with the same density. After calibration, the simulations reproduce the observed grave-sand sheet propagation in the overfeeding experiments. Simulations of the tests of different density classes indicate that coarse, low-density particles exhibit higher mobility than equally sized quartz particles, while the mobility of fine, low-density particles is comparable to that of natural sand of similar size. The model provides a consistent and conservative framework for representing the coupled transport and sorting of sediment–plastic mixtures in open-channel flows.

Acknowledgement: This works was supported by the Portuguese Foundation for Science and Technology (FCT) through project Project DT4Rivers COMPETE2030‐FEDER‐00760800 and European Union through Interreg Atlantic 2021-2017 project TRAP – EAPA_0122/2024

How to cite: Ricardo, A. M., L Ferreira, R. M., Varrani, A., Guerrero, M., Rowinski, P., and Mrokowska, M.: A model for the fluvial transport of different size and density classes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22114, https://doi.org/10.5194/egusphere-egu26-22114, 2026.

Whether we talk about safety reasons, energy production or regulation, water resources management is one of EDF’s (Électricité De France, French hydropower company) main concerns.

The range of water-based activities is steadily increasing : paddleboarding, canoeing, float-tube fishing, these floating crafts are now widely available at low cost and are becoming popular on rivers. EDF’s hydroelectric facility operators are regularly faced with the intrusion of swimmers and watercraft near the structures. This occurs, for example, beyond the restricted zone upstream of hydroelectric installations. This zone, usually marked by a line of buoys, is intended to prevent drowning accidents that could result from the start-up of a turbine or any other system capable of creating a suction current. Similar risks exist downstream of the structures, where currents and depths attract swimmers and floating crafts.

Given the risky behavior of river users, EDF’s challenge is to secure the vicinity of its installations by assessing the danger and proposing appropriate countermeasures. In this context, EDF aims at determining current thresholds beyond which the swimming ability and maneuvering capacity of floating crafts (paddleboards, canoes, float-tubes) for different user profiles (children, adults, athletes) are no longer sufficient to escape the danger of being sucked in or swept away. This study therefore only concerns areas where users cannot stand in the river. Such work will enable the company to implement the necessary measures to secure zones considered hazardous near hydroelectric structures.

To carry out this work, tests in collaboration with members of the SDIS 81 Water Rescue team were conducted at the Millau whitewater stadium to determine the current speeds beyond which swimmers and light watercraft can no longer escape danger. These trials, carried out under controlled and safe conditions, involved scenarios of swimming and maneuvering floating crafts in currents ranging from weak to strong at the Millau water sports facility. The objective was to assess the swimming and mobility capacities of swimmers and non-motorized watercraft (paddleboards, canoes, float-tubes) across different current speed ranges.

All the tools routinely used by EDF hydrometric teams to measure flow velocities were deployed (ADCP, current meter, SVR radar, LSPIV) to better characterize the different current speeds tested.

The results obtained made it possible to identify the threshold values sought, based on current speed and the presence or not of turbulence. Finally, a theoretical approach based on Newton’s second law helped corroborate the empirical results obtained during the tests.

How to cite: Morlot, T., Belleville, A., and Le Brun, M.: Risk near hydroelectric structures – Determination of critical velocity thresholds for river users (swimmers and floating crafts), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3833, https://doi.org/10.5194/egusphere-egu26-3833, 2026.

River discharge is a key indicator for water resources management and flood forecasting; however, the traditional single stage–discharge rating curve used for its estimation produces systematic errors under unsteady flow conditions due to hysteresis. In this study, field-measured Manning’s roughness coefficients (n) are first estimated at Naju Bridge on the Yeongsan River by combining H-ADCP–measured discharges with water-surface slopes derived from upstream and downstream stage observations, using the continuous slope–area (CSA) framework in inverse form. The resulting 10-min n time series for the 2020 flood events is then segmented by stage to represent cross-sectional controls on roughness. These stage-wise n segments are subsequently applied to the CSA method to compute discharge time series for the 2019 and 2021 flood events, and the estimates are validated against observations. The estimated n exhibits a consistent stage-dependent pattern, including a rapid decrease at low stages, convergence at intermediate stages, an inflection point near the onset of rapid cross-sectional expansion, and an increase at high stages, reaching n ≈ 0.08–0.09 during extreme floods—values higher than those from conventional empirical formulas and design criteria. Using the measured and stage-segmented n, the CSA-based discharge estimates successfully reproduce hysteresis across six flood events, achieving R² ≥ 0.94 and peak error ≤ 3%, although nRMSE exceeds 10% under low-flow conditions. Overall, applying field-derived roughness substantially improves CSA discharge estimation and supports the practical use of roughness monitoring and CSA-based computation in rivers subject to unsteady flow.

How to cite: Ikhan, L., Dongsu, K., Dohyeon, K., Gibeom, S., and Jonghyeon, Y.: Field Estimation of Manning’s Roughness and Its Application to CSA Discharge Computation during Flood Events, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4747, https://doi.org/10.5194/egusphere-egu26-4747, 2026.

Sediment transport is a key process in fluvial geomorphology, particularly in gravel-bed rivers, as it controls channel morphology and has important implications for river management and restoration. This process occurs in three main phases: entrainment, movement, and deposition, and is influenced by factors such as particle size, shape, density, angularity, imbrication, and the ratio between transported sediment size and bed material.  Although field data on sediment transport are essential, they are often difficult to obtain. To overcome this, a wide range of monitoring techniques has been developed, including direct samplers such as the Helley-Smith sampler and bedload traps, acoustic sensors such as geophones and hydrophones, and laboratory experiments that allow sediment dynamics to be studied under controlled conditions. In parallel, sediment transport models rely strongly on grain size distribution, either using the full distribution or representative metrics such as D50 or D84. Since the 1990s, sediment tracking has become increasingly important, with gravel tagging emerging as a widely used method for analysing sediment mobility and travel distances. Technological advances have significantly improved recovery rates, particularly through the use of electronic tags. Passive Integrated Transponder (PIT) tags are now commonly used due to their small size, low cost, long lifespan, and passive operation. Active tags, such as VHF and UHF, enable continuous tracking via fixed antennas but are larger and more expensive. In this work, we used active tags to estimate the volume of sediment mobilised by deploying RFID‑tagged gravels, thereby improving our understanding of sediment movement through the concept of virtual velocity. Tag seeding was carried out at four sites upstream of the first fixed antenna. Preliminary results show that gravels in the 45–181 mm size range (85% of all seeded material) have been mobilised over distances of approximately 700 m and detected by the antennas, whereas gravels in the coarsest size classes have not yet been recorded. In conclusion, higher‑magnitude events are required for the coarsest particle sizes to become mobile and be detected by the first antenna. Although several low‑magnitude events have occurred, very few of the mobilised gravels have been detected by the second antenna located downstream of the first, suggesting that they may have become buried or trapped in pools.

ACKNOWLEDGMENTS: This work is funded by the European Research Council (ERC) through the Horizon Europe 2021 Starting Grant program under REA grant agreement number 101039181 - SEDAHEAD.

How to cite: Juez, C. and Rabanaque, M. P.: Sediment mobility in a gravel-bed river (Aragón Subordán River, Central Spanish Pyrenees) assessed using active RFID tags, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7104, https://doi.org/10.5194/egusphere-egu26-7104, 2026.

River flow conditions at high latitudes show strong seasonal variability due to changes in hydrological conditions throughout the year. During winter, ice cover reduces flow velocity. In spring, snowmelt increases discharge and often results in flooding. During summer and autumn, rainfall can cause temporary increases in discharge. High-latitude fluvial environments are particularly sensitive to climate change, which has been found to have a stronger impact in these regions than in rivers at lower latitudes. This study investigated seasonal flow dynamics in a single meander bend of the Oulankajoki River in Finland during winter, spring, and autumn over one hydrological year using an Acoustic Doppler Current Profiler (ADCP). Vertical ADCP surveys provided detailed cross-sectional velocity profiles and flow directions throughout the water column in each field campaign.

Results showed significant variation between seasons. Winter ice cover significantly reduced near-surface velocities and shifted the high-velocity core (HVC) to mid-depth, whereas in open-water conditions the highest velocities occurred closer to the surface. In open-channel conditions, peak velocities were observed in the shallow upstream and deep downstream sections of the bend, while in winter flow decelerated downstream of the bend apex.  During winter and autumn, the HVC was located near the inner bank in the upstream section of the meander bend and gradually shifted to the outer bank before the bend apex. Downstream of the apex, the HVC migrated from the outer bank toward the center of the channel. Unlike in winter and autumn, the spring flood caused the HVC to migrate from the upstream of the meander, flow directly across the point bar, and shift toward the outer bank at the apex.

The study is now being extended by integrating continuous monitoring of flow conditions using a side-looking Doppler current meter. This enables long-term, high-resolution observations, including ice-covered periods. Combining vertical and horizontal ADCP measurements is expected to provide a rare, spatially comprehensive and temporally continuous dataset. This integration enables improved characterization of flow variability and seasonal dynamics in high latitude rivers, thereby enhancing hydrological analyses and process-based modeling.

How to cite: Korkiakoski, K.: From short-term vertical ADCP measurements to continuous Side-Looking current meter monitoring in a high-latitude river, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7246, https://doi.org/10.5194/egusphere-egu26-7246, 2026.

Ensuring the safety of spillways during flood events is a critical challenge for dam operators and public authorities. Accurate knowledge of flow velocities along spillways and downstream of ski jumps is essential for assessing the erosive potential of high‑velocity flows and preventing structural damage. However, intrusive velocity measurement techniques are unsuitable in such configurations due to limited accessibility and the very high flow speeds involved. Image‑based velocimetry offers an attractive alternative, providing instantaneous, spatially distributed velocity fields from a single viewpoint. Yet, conventional image-based techniques rely on the assumption of a planar free surface, which becomes invalid for curved flows such as those encountered on spillway chutes or nappe flows. Surface curvature induces geometric distortions in ortho‑rectified images, leading to significant velocity errors.

Stereo‑vision systems can be used to reconstruct non‑planar free surfaces, but their deployment on full‑scale spillways is complex and costly as it requires synchronized cameras with high spatial and temporal resolution. To overcome these limitations, we propose OrthoCyd, a novel single‑camera orthorectification method dedicated to flows whose free‑surface geometry is known a priori and corresponds to a right‑cylindrical surface (i.e., a planar surface which is curved along the longitudinal dimension). This approach is well suited to spillway chutes, with the assumption that the free surface follows the underlying curved geometry. OrthoCyd enable consistent displacement measurements with any image-velocimetry method (block matching, tracking, optical flow, spatio-temporal approach). This method extends the applicability of image‑based velocimetry to non‑planar free‑surface flows while maintaining the simplicity and practicality of single‑camera acquisition systems.

Two applications illustrate the method: a laboratory experiment on a free‑nappe flow, and a field application on an operating spillway. These examples demonstrate that OrthoCyd provides reliable velocity measurements in both controlled and full‑scale conditions.

How to cite: Bodart, G., Hauet, A., Le Coz, J., and Jodeau, M.: Applying image velocimetry on curved free‑surface geometries of known shape such as spillways or free-nappe: the OrthoCyd method., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7926, https://doi.org/10.5194/egusphere-egu26-7926, 2026.

Recently, non-contact current meters (radar, image-based) are widely used to measure the discharge of rivers, and research and cases of calculating discharge by applying surface velocity-based index velocity method and velocity distribution method are increasing. To apply index velocity or velocity distribution methods based on surface velocity, the relationship between the surface velocity used as the index velocity and the cross-sectional average velocity must be known. In general, in straight channels with sufficiently large channel width, the ratio of the cross-sectional average velocity to the maximum velocity (ϕ(M)) is known to be between 0.6 and 0.7.

In this study, the relationship between the maximum surface velocity and the cross-sectional average velocity was analyzed. Using 179 flow measurement data from 60 sites, the ratio of the cross-sectional average velocity to the maximum surface velocity (≈ϕ(M)) was calculated. As a result, ϕ(M) was analyzed to have an average of 0.64(correlation coefficient R=0.86). When the relationship between the two elements was established as a linear equation, the slope was calculated to be 0.6306 (R=0.74). The ratio of ϕ(M) and the velocity coefficient α (ratio of reference discharge/surface velocity discharge (α=1 applied)) was calculated to be 0.75 on average (range 0.51 to 0.91), and when the relationship between the two elements was established as a linear equation, the slope was calculated to be 0.7586 (R= 0.68). The correlation coefficient between ϕ(M) and the maximum surface velocity/average surface velocity of the cross-section was calculated to be -0.84, indicating that ϕ(M) shows a strong correlation with the distribution characteristics of the surface velocity. When the relationship between the two factors was established as an exponential equation, the coefficient of determination was calculated to be 0.76, confirming that the value of ϕ(M) can be estimated and used through surface velocity measurements.

keyword : average velocity, surface velocity, index velocity, ϕ(M)

How to cite: Lee, S., Jang, B., and Lee, J.: Relationship between Cross-Sectional Mean Velocity and Surface Velocity in Rivers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8486, https://doi.org/10.5194/egusphere-egu26-8486, 2026.