Heterogeneous Coulomb stress perturbation during earthquake cycles in a 3D rate‐and‐state fault model

Abstract

We perform a numerical experiment with quasi‐dynamic continuous 3D fault model governed by a laboratory derived rate‐and‐state friction law. We test several cases in which the Coulomb stress (CS) increases either on the whole fault or only on its part. For the partial stressing we find that if the triggering is almost instantaneous (within 1–2 months), the nucleation takes place in the strike extent of the CS increase area. On the contrary, if the earthquake does not occur within these few months, it can nucleate anywhere on the fault, and even later than without the positive CS load. These features represent new findings which are unique for 3D model and cannot be explained by 1D spring‐slider models. The finding might find applications in the aftershock (time‐dependent) seismic hazard assessment.