HR: 1330h
AN: S52A-0109    [PDF]
TI: Estimation of Dynamic Stress Parameters of the 1992 Landers Earthquake
AU: * Pitarka, A
EM: arben pitarka@urscorp.com
AF: URS Corporation, 566 El Dorado St., Pasadena, CA 91101 United States
AU: Dalguer, L A
EM: dalguer@egmdpri01.dpri.kyoto-u.ac.jp
AF: DPRI, Kyoto University, Gokasho, Uji, Kyoto, 611 Japan
AB: We apply a slip-weakening friction model of rupture dynamics to determine the dynamic stress-drop, strength excess and critical slip for the 1992 Landers earthquake. We follow a two step procedure. First, based on the slip distribution on the fault and the rupture time obtained from a kinematic model of the fault rupture (Wald and Heaton,1994), we compute the shear-stress change on the fault during the earthquake using a finite-difference method of fourth-order accuracy. We use a vertically heterogeneous velocity model and a single planar fault. Using the shear-stress change we derive the distribution of approximate values of the dynamic and static stress drop, and strength excess. The slip weakening distance is obtained using the approach of Mikumo (2003) which uses the slip-velocity and the time history of the shear stress. Second, based on finite-difference forward modeling of the recorded motion using dynamic modeling of the fault rupture, the dynamic stress parameters are adjusted by a trial and error scheme. The final model is the one that best fits the total slip obtained by the kinematic model, and the recorded ground motion in the frequency range of 0.1-0.5 Hz.
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2003 Fall Meeting