HR: 1330h
AN: S42C-0190    [PDF]
TI: Examining tendencies of in-plane rupture to migrate to material interfaces
AU: * Brietzke, G
EM: brietzke@geophysik.uni-muenchen.de
AF: Deparment for Earth and Environmental Sciences, LMU Munich, Theresienstr. 41, Munich, 80333 Germany
AU: Ben-Zion, Y
EM: benzion@terra.usc.edu
AF: Department for Earth Sciences, USC Los Angeles, University Park Campus, Los Angeles, CA 90089 United States
AB: Recent work indicated that rupture along a material interface has remarkable dynamic properties, which may be relevant to a number of geophysical problems, and that material interfaces are mechanically favoured locations for rupture propagation. Here we examine tendencies of 2D in-plane rupture to migrate spontaneously to material interfaces by performing a numerical parameter-space study in a model consisting of 3 media with 9 possible faults, 2 of which are material interfaces. The calculations employ a generalized version of the second-order finite-difference code used by Andrews (1973) and Andrews \& Ben-Zion (1997). The faults are governed by Coulomb friction, and in some cases also Kelvin-Voigt viscosity. In general, a rupture along a material interface governed by Coulomb friction does not have a continuum limit (e.g., Adams, 1995; Ranjith \& Rice, 2001). A Kelvin-Voigt viscosity provides regularization of the problem for a limited range of propagation distances and grid-refinements. Ruptures in our work are nucleated by a symmetric bilateral expanding pore pressure source, and may then continue to propagate (or not) along one or more faults. Using different nucleation locations (fault 1-9), different rheological parameters and initial stress, and different velocity contrasts, we examine the range of conditions for which ruptures migrate spontaneously to material interfaces and continue to propagate there in a self-sustaining manner.
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics and mechanics
SC: Seismology [S]
MN: 2003 Fall Meeting