Genesis of mega-thrust earthquakes events at convergent plate boundaries: 3Dmodelling of seismic coupling combining geodynamic and earthquake-faulting models

Ylona van Dinther (ETHZ), Dr. Taras Gerya (ETHZ), Dr. Luis A. Dalguer (ETHZ), Dr. P. Martin Mai, (KAUST, Saudi Arabia), Dr. Gabriele Morra (University of Sydney, Australia), Dr. Francesca Funiciello (University Roma Tre, Italy)

Here we develop a coupled system of geodynamic and earthquake faulting dynamic models to investigate long‐term earthquake cycle on a convergent margin, starting from geodynamic large space‐time scales, sequentially progressing to small space‐time scales to cover the range of interest. Our numerical simulations link kinematic observables and long‐term deformation phenomena to earthquake dynamic occurrences. This investigation contributes to understand the physical relationship between geodynamic mechanisms, seismicity and thrust-faulting dynamics. Our current geodynamic simulations (see figure below) shows outer‐rise localization features, influenced by both regional and bending stresses, characterized in terms of seismic properties. The development of this works requires extremely high computation to cover the complete process of earthquake occurrences at small and large scales in time and space.

_{Figure: Geodynamic visco-elasto-plastic 1500x200 km subduction model showing a) compositional rock type with temperature contours (red), and iso-viscosity surface (white), b) viscosity, c) second invariant of the deviatoric stress tensor, and d) second invariant of the deviatoric strain rate tensor. Numbers depict different plastic strain localization areas; 1) thrust fault, 2) trench-ward outer-rise bending faults, 3) back-arc normal faults, and 4) wedge-confining faults.}