Modeling of Unilateral Rupture Along Very Long Reverse Faults

Abstract

AbstractWe evaluate the mechanism for horizontal unilateral rupture frequently observed along very long reverse faults in subduction zones or inland regions using mathematical models and numerical experiments. We consider a situation where the direction of maximum shear stress acting on the fault surface is not parallel to the fault plane. Furthermore, by incorporating the effects of the bimaterial interface and off‐fault inelastic deformation into the model, we demonstrate that acceleration of dynamic rupture in only one direction is possible. The mathematical modeling reveals that the asymmetric rupture is due to the asymmetric off‐fault damage interacting with asymmetric off‐fault stress intensity driven by the above effects. Finally, for three oblique subduction zones, we found that the rupture patterns of 8 of 11 megathrust events were consistent with the mechanism proposed in this study.