HR: 11:20h
AN: S32B-05 INVITED     [Abstracts]
TI: Variation of large elastodynamic earthquakes on complex fault systems
AU: * Shaw, B E
EM: shaw@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AB: One of the biggest assumptions, and a source of some of the biggest uncertainties in earthquake hazard estimation is the role of fault segmentation in controlling large earthquake ruptures. Here we apply a new model which produces sequences of elastodynamic earthquake events on complex segmented fault systems, and use these simulations to quantify the variation of large events. We find a number of important systematic effects of segment geometry on the slip variation and the repeat time variation of large events, including an increase in variation at the ends of segments and a decrease in variation for the longest segments. We find both quantitative and qualitative differences between slip variation and time variation, so slip variation and time variation are not simple proxies for eachother. The model both generates self-consistent complex fault geometries, and generates self-consistent elastodynamic events on those geometries. This geometrical self-consistency is important in insuring strain is compatibly accommodated in t he long run over many earthquake cycles. The self-consistency also reduces the number of things which must be specified, by allowing the fault system to self-organize from a simple physics. Because of the numerical efficiency of the model, we can generate long sequences of events, and study the statistics of the populations. The long sequences are critical here in that the stresses left over by previous events form the setting for subsequent events. With this model, we can thus begin to address the fundamental questions of the interaction of geometry and dynamics over many earthquake cycles.
DE: 7221 Paleoseismology
DE: 7223 Seismic hazard assessment and prediction
DE: 7260 Theory and modeling
DE: 8010 Fractures and faults
DE: 7209 Earthquake dynamics and mechanics
SC: Seismology [S]
MN: 2004 AGU Fall Meeting