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Inelastic Response of Compliant Fault Zones to Nearby Earthquakes in Three Dimensions

Jingqian Kang, & Benchun Duan

Published December 4, 2014, SCEC Contribution #1776

Using dynamic modeling of earthquake rupture on a strike-slip fault and seismic wave propagation in a three dimensional inhomogeneous elastoplastic medium, we investigate the response of compliant Fault Zones (FZs) to nearby earthquakes. We primarily examine the plastic strain distribution within the FZ and the residual displacement field that characterizes effects of the presence of the FZ. We find that when the FZ rocks are close to failure in the prestress field, plastic strain occurs along the entire FZ near surface, and some portions of the FZ in the extensional quadrant at depth. Plastic strain enhances the surface displacement of the FZ, and the enhancement in the extensional quadrant is stronger than that in the compressive quadrant. This finding suggests that large residual displacements caused by inelastic response of a fault zone may be mapped into inaccurate estimations of the fault-zone structure and property if elastic response is assumed. Identifying inelastic response of nearby FZs to large earthquakes may allow us to place some constraints on the absolute stress level in the crust.

Kang, J., & Duan, B. (2014). Inelastic Response of Compliant Fault Zones to Nearby Earthquakes in Three Dimensions. Tectonophysics,. doi: 10.1016/j.tecto.2013.11.033.