Spontaneous Rupture Propagation on a Non-planar Fault in 3-D Elastic Medium

Abstract

—We constructed a new calculation scheme of spontaneous rupture propagation on non-planar faults in a 3-D elastic medium using a boundary integral equation method (BIEM) in time domain. We removed all singularities in boundary integral equations (BIEs) following the method proposed by Fukuyama and Madariaga (1995, 1998) for a planar fault in a 3-D elastic medium, and analytically evaluated all BIEs for a basic box-like discrete source. As an application of the new calculation scheme, we simulated rupture propagation on a bending fault subjected to uniform triaxial compression and examined the effect of fault bend upon the dynamic rupture propagation. From the numerical results, we found that rupture propagation is decelerated or arrested for some combination of inclined angle of the bending fault and absolute value of the fault strength. The most significant effect of bending is the nonuniform distribution of pre-loaded shear stress due to different orientation of the fault plane under a uniform tectonic stress regime. Our results also indicate that low absolute shear stress level is required to progress the rupture propagation ahead of the inclined fault.