SEV – Side Events

LRS1 – The Bullerwell Lecture of the British Geophysical Association

EGU22-3965 | Presentations | LRS1

Seismicity and the deformation of subducting slabs

Tim Craig

Earthquakes associated with the subduction of tectonic plates into the Earths’ interior occur in four dominant settings: (i) major seismic failure on the interface between the two plates (the subduction “megathrust”); (ii) shallow crustal earthquakes within the overriding plate; (iii) earthquakes within the outer rise region of the downgoing plate, as it bends into the subduction zone; and (iv) earthquakes that occur within the subducting slab as it descends into the mantle. These latter two classes of earthquakes reflect the internal deformation of the downgoing plate, and are the focus for this talk.  

Both of these types of intraslab, or intraplate, earthquakes are principally driven by bending of the plate.  The bending and flexure of subducting plates creates complex stress and strain fields, which are highly variable across short distances, both vertically and laterally.  This leads to complex patterns of intraplate seismicity, which offers our principal insight into the dynamics of the subducting slab.  Beyond this, these intraslab earthquakes offer our main observational constrains on the rheology of the slab, and its rheological evolution over the its initial stages of subduction.  From the potential for fluid infiltration into the subducting plate at the outer rise, to the role that metamorphism and fluid release play in permitting intermediate depth intraslab seismicity, these earthquakes also relate to the chemical evolution of the plate during subduction.  Lastly, although less common, and usually smaller in magnitude, than earthquakes occurring on the subduction interface, intraplate subduction zone earthquakes pose a critical, and often under-appreciated, hazard for the overlying regions, particularly given their potential to trigger secondary hazards in the setting of the supra-subduction arc.

Here, I will consider earthquakes associated with the internal deformation and bending of subducting plates through the initial phases of subduction, from an intact oceanic plate entering the subduction zone to the descent of the plate into the mid-mantle, the controls on their occurrence, and their geodynamic implications. 

How to cite: Craig, T.: Seismicity and the deformation of subducting slabs, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3965, https://doi.org/10.5194/egusphere-egu22-3965, 2022.

LRS2 – 16th C.F. Gauss Lecture

EGU22-11405 | Presentations | LRS2

Supercomputing of large earthquakes

Alice-Agnes Gabriel

Earth modeling is extraordinarily complex - and when the earth quakes, it’s no different. Earthquakes are highly non-linear and multiscale processes fracturing the Earth’s crust and emanating potentially destructive seismic waves. While computational seismology has been a pioneering field for high-performance computing, the multitude of scales and multi-physics character of earthquake source processes remain difficult to constrain.

Earthquake science is increasingly data-rich, which opens up new pathways to synergistically integrate seismological, geodetic, tectonic and experimental analysis in multi-physics forward modeling. Using a physics-based description of earthquakes, interdisciplinary earthquake observations,  modern numerical methods and hardware specific optimisation shed light on the dynamics, severity and cascading hazards of earthquake behaviour. An unparalleled degree of realism is enabled by exploiting high-performance computing.

In this lecture, I will demonstrate the potential of Solid Earth community software for performing data-integrated, parsimonial scenarios of recent powerful multi-fault earthquake cascades, 3D fully-coupled Earth and ocean models of tsunami generated during earthquakes as well as cycles of earthquake and aseismic slip using petascale supercomputers. The inclusion of probabilistic and Bayesian frameworks, geometric transformations and diffuse interface approaches are future directions I will discuss for exploiting the expected exascale computing infrastructure.

How to cite: Gabriel, A.-A.: Supercomputing of large earthquakes, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11405, https://doi.org/10.5194/egusphere-egu22-11405, 2022.

CC BY 4.0