Large‐scale characteristics of plate boundary deformations related to the post‐seismic readjustment of a thin asthenosphere

Abstract

The large‐scale response of an elastic lithosphere, riding on a ‘thin’ viscoelastic asthenosphere, to periodically occurring ruptures at a transform or subduction‐type plate boundary is described approximately by appropriate limit cycle solutions for a plate/foundation model introduced previously by Rice. The cyclic behaviour of thickness‐averaged displacements, strains and strain rates, their decay away from the plate boundary, and a resolution into coseismic and post‐seismic alterations are obtained and their dependence on repeat time and a characteristic relaxation time investigated. A comparison is made with existing periodic solutions for the surface deformations in a Nur‐Mavko half‐space model. This suggests important effects due to viscosity stratification on post‐seismic rebound when earthquake repeat times exceed relevant relaxation times by at least one order of magnitude. Copyright © 1982, Wiley Blackwell. All rights reserved