Inelastic response of compliant fault zones to nearby earthquakes

Abstract

Using dynamic rupture models, we examine the response of compliant fault zones that surround pre-existing faults to nearby earthquakes. We find that some portions of a compliant fault zone can experience inelastic deformation due to dynamic stress perturbations, while the remaining portions deform elastically. Inelastic response of the fault zone results in sympathetic fault-parallel motion (i.e., consistent with long-term geologic slip) across the fault, while elastic response causes retrograde motion (i.e., opposite to long-term geologic slip) in the static displacement field. Inelastic deformation signals along fault zones detected geodetically may be used to constrain the stress state in the crust because inelastic response occurs only when the prestress level is close to material strength, which can be measured in the laboratory. © 2010 by the American Geophysical Union.