HR: 08:45h
AN: NG31A-04 INVITED     [Abstracts]
TI: Role of Stress Relaxation in Slip of Geometrically Complex Faults
AU: * Dieterich, J H
EM: dieterichj@ucr.edu
AF: University of California, Riverside, Department of Earth Sciences, Riverside, CA 92521 United States
AB: A long-established representation of faults in standard earthquake models is that of a planar slip surface embedded in an elastic medium. The planar fault representation is, of course, highly idealized - faults surfaces have irregularities over a very wide range of wavelengths and form branching structures and networks. Some effects of fault complexity have been investigated with models of single faults that have a random fractal roughness. In addition to geometrically controlled fluctuations of slip along the fault, the elastic models of non-planar faults display a variety of phenomena not seen in planar fault models. These include, systematic decrease of total slip with increasing amplitude of fault roughness, modification of the shape of the of the overall slip distribution along the fault, and non-linear scaling of fault slip by fault length. These various phenomena are all connected to stress heterogeneities in the elastic medium that grow with cumulative total slip. In real materials these stresses cannot increase without limit - indicating that stress relaxation by local yielding or secondary faulting must be an important element of the processes controlling fault slip. The stress relaxation processes may be manifest in part as aftershocks, and in part by slip on secondary faults during earthquakes.
DE: 7209 Earthquake dynamics (1242)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005