The Influence of Depth?Varying Elastic Properties of the Upper Plate on Megathrust Earthquake Rupture Dynamics and Tsunamigenesis

Megathrust earthquakes are strongly influenced by the elastic properties of rocks surrounding fault. In contrast to friction, these can be derived in situ from geophysical measurements along seismogenic zone. However, they often overestimated numerical simulations, particularly shallow megathrust. Here we explore influence that realistic depth-varying upper-plate megathrust have on earthquake rupture dynamics and tsunamigenesis using 3D dynamic tsunami simulations. We compare results three subduction zone scenarios with homogeneous heterogeneous media, bimaterial Elastic model follow a depth-distribution controlled-source tomography models zones. assume same friction for all scenarios. Simulations show rigidity depth variations explain behavior slip, slip rate, frequency content, time. The duration quantitatively agree previous predictions based worldwide data compilations, explaining main depth-dependent traits large earthquakes. Large slow rate amplification simulations largely controlled rock most compliant side fault, which zones is upper plate. trenchward increasing compliance lead largest co-seismic seafloor deformation amplitude. This highlights importance considering properly assess tsunamigenic potential