Slip stability at heterogeneous interfaces with large-slip kinematics

Abstract:

The study of stability of steady sliding between elastically deformable continua using rate- and state-dependent friction laws provides insights into the characteristics of earthquake rupture. While some studies have considered the effects of having dissimilar solids and heterogeneous frictional properties, the description has not addressed the kinematics of large slip---an aspect that is relevant to spatially complex fault zones in nature.

Here, we consider two homogeneous elastic solids, treated as half-space continua, in steady frictional sliding . The interface between the elastic solids is heterogeneous, where the frictional properties vary in space. We describe motion of the contacting surfaces using Eulerian and Lagrangian frames of reference, and demonstrate that the current formulation of rate-and-state friction fails to account for the frictional evolution at large slip distances.

We develop a novel formulation of rate-and-state friction that incorporates the fundamental notion of roughness transport on both sides of the frictional contact. We then use it to study, in the context of elastodynamics, the stability of steady sliding at the interface. The focus is on the linearized response to in-plane perturbations of steady-state sliding. In the quasi-static limit, we investigate questions of earthquake nucleation, size, and location.