HR: 17:45h
AN: S14C-08    [Abstracts]
TI: Developing a physics-based finite source characterization tool for strong ground motion simulation of large earthquakes
AU: * Song, S
EM: Seok_Goo_Song@URSCorp.com
AF: URS Corporation, 566 El Dorado Street, Pasadena, CA 91101-2560,
AU: Pitarka, A
EM: Arben_Pitarka@URSCorp.com
AF: URS Corporation, 566 El Dorado Street, Pasadena, CA 91101-2560,
AU: Beroza, G C
EM: beroza@pangea.stanford.edu
AF: Stanford University, 397 Panama Mall, Stanford, CA 94305-2215,
AB: Accurate prediction of the intensity and variability of near-field strong ground motion for future large earthquakes strongly depends on our ability to simulate realistic earthquake source models for those events. We developed a pseudo-dynamic source modeling method that generates kinematic, but physically self-consistent, finite-source models that include important characteristics of dynamic rupture. This approach was first initiated by Guatteri et al. (2004) for moderate size events and we extend its magnitude coverage to larger strike-slip crustal earthquakes (M > 7.2). We base the new pseudo-dynamic source models on 15 spontaneous dynamic rupture models that were constructed with different slip realizations and hypocenter locations for large, Mw 7.5, strike-slip events. These earthquakes have very long and narrow rupture dimensions (150 km long and 15 km wide), which leads to substantially different source scaling behavior than the smaller events used by Guatteri et al. (2004). We also allow greater latitude for supershear rupture in the present study, because it has been observed recently for a large strike-slip earthquakes (Bouchon et al., 2001; Bouchon and Vallèe, 2003; Dunham and Archuleta, 2004; Das, 2007; Song et al., 2008). Supershear rupture is widely observed in our modeling, and we find that instantaneous (local) rupture velocity correlates strongly with local slip amplitude. We also find that the limited fault width of these long, narrow ruptures exerts a critical control on rupture behavior as predicted by Day (1982). Our improved pseudo-dynamic modeling method can be used to generate realistic finite-source earthquake models for simulating near-field ground motions from large strike-slip events. This will help us to improve our limited knowledge about near-field ground motion characteristics because of the lack of observed data.
DE: 7209 Earthquake dynamics (1242)
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7290 Computational seismology
DE: 8118 Dynamics and mechanics of faulting (8004)
SC: Seismology [S]
MN: 2007 Fall Meeting