HR: 1340h
AN: S13D-1085    [Abstracts]
TI: Dynamics of Stress-Field Proxies Associated With Large Earthquake Cycles in a Quasidynamic Fault Model
AU: * Z{\"o}ller, G
EM: zoeller@rz.uni-potsdam.de
AF: Institute of Physics, University of Potsdam POB 60 15 53, Potsdam, 14415 Germany
AU: Hainzl, S
EM: hainzl@geo.uni-potsdam.de
AF: Institute of Earth Sciences, University of Potsdam POB 60 15 53, Potsdam, 14415 Germany
AU: Holschneider, M
EM: hols@math.uni-potsdam.de
AF: Institute of Mathematics, University of Potsdam POB 60 15 53, Potsdam, 14415 Germany
AU: Ben-Zion, Y
EM: benzion@usc.edu
AF: Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740 United States
AB: We use the recently developed quasidynamic model of a discrete strike-slip fault in an elastic solid (Z{\"o}ller et al., 2004) to study proxies of the stress field on the fault in relation to large earthquake cycles. The model, based on earlier work of Ben-Zion and Rice (1993) and Ben-Zion (1996), is governed by realistic boundary conditions, static-kinetic friction, aseismic creep, and stress-transfer for static dislocations in an elastic half-space (Chinnery, 1963). The dynamic rupture is approximated by stress propagation with a constant velocity. Model simulations over thousands of years show that important properties of observed seismicity, e.g. distributions of the earthquake sizes, times and hypocenters, can be reproduced. A key question for time-dependent seismic hazard assessment is the identification of the state of an earthquake cycle at a given time. This requires knowledge of the stress on the fault, which is known in the model, but not accessible for real fault systems. Therefore, we search for useful proxies for the stress field in the framework of the above model. In addition to various seismicity-based signals, a possible proxy is the surface displacement field, which can be determined by geodetic arrays. Using model realizations with different amount of heterogeneities, representing different evolutionary stages of a fault, we discuss the ability of such quantities to identify stages of a large earthquake cycle on a fault.
DE: 7223 Seismic hazard assessment and prediction
DE: 7260 Theory and modeling
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
DE: 3210 Modeling
SC: Seismology [S]
MN: 2004 AGU Fall Meeting