Stress Heterogeneity and the Onset of Faulting Along Geometrically Irregular Faults

Abstract

We present a two-dimensional analytical solution for the static stress field around a rough interlocked interface under background stresses and its applications to faulting. The solution is derived using perturbation theory for the defined interface topography and background stresses. The failure-ratio, which scales the likelihood to failure of the bulk material around the interface, is calculated adopting the Coulomb failure criterion. We compare model predictions with results of experiments performed on rough rock interfaces and find good agreement between the locations of off-fault deformation zones and calculated high failure-ratio values. We further study the effect of fault topography on stress distribution and failure around the San Andreas Fault and find a moderate correlation between Failure-Ratio values and off-fault seismic events. We conclude that our model is able to delineate off-fault regions that are relatively prone to bulk failure due to local effects of fault topography.