HR: 1330h
AN: S42D-0193    [PDF]
TI: Rupture Propagation for Stochastic Fault Models
AU: Favreau, P
EM: pfavre@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4, Place Jussieu, PARIS CEDEX 05, 75252 France
AU: * Lavallee, D
EM: daniel@crustal.ucsb.edu
AF: Institute for Crustal Studies. University of California at Santa Barbara, UCSB, Santa Barbara, CA 93106 United States
AU: Archuleta, R
EM: ralph@crustal.ucsb.edu
AF: Institute for Crustal Studies. University of California at Santa Barbara, UCSB, Santa Barbara, CA 93106 United States
AB: The inversion of strong motion data of large earhquakes give the spatial distribution of pre-stress on the ruptured faults and it can be partially reproduced by stochastic models, but a fundamental question remains: how rupture propagates, constrained by the presence of spatial heterogeneity? For this purpose we investigate how the underlying random variables, that control the pre-stress spatial variability, condition the propagation of the rupture. Two stochastic models of prestress distributions are considered, respectively based on Cauchy and Gaussian random variables. The parameters of the two stochastic models have values corresponding to the slip distribution of the 1979 Imperial Valley earthquake. We use a finite difference code to simulate the spontaneous propagation of shear rupture on a flat fault in a 3D continuum elastic body. The friction law is the slip dependent friction law. The simulations show that the propagation of the rupture front is more complex, incoherent or snake-like for a prestress distribution based on Cauchy random variables. This may be related to the presence of a higher number of asperities in this case. These simulations suggest that directivity is stronger in the Cauchy scenario, compared to the smoother rupture of the Gauss scenario.
DE: 3230 Numerical solutions
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
DE: 7260 Theory and modeling
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2003 Fall Meeting