HR: 11:05h
AN: S22B-03    [Abstracts]
TI: Physics-Based Characterized-Source Modeling for Strong Motion Prediction
AU: * Irikura, K
EM: irikura@egmdpri01.dpri.kyoto-u.ac.jp
AF: Kyoto Univ., Yoshida Honmachi, Sakyo, Kyoto, 606-0011 Japan
AU: Miyake, H
EM: hiroe@eri.u-tokyo.ac.jp
AF: ERI, Univ. Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-0032 Japan
AU: Dalguer, L A
EM: ldalguer@moho.sdsu.edu
AF: San Diego State Univ., 5500 Campanile Drive, San Diego, CA 92182-1020 United States
AB: From recent development of the kinematic waveform inversion to investigate rupture process, we have understood that strong ground motion is relevant to slip heterogeneity inside the source rather than average slip in the entire rupture area. The most important parameters featuring strong ground motions are sizes of asperities and effective stress on each asperity, which characterize the amplitudes and periods of directivity pulses causing earthquake damage. Systematic analyses of slip inversions indicate that the asperity areas as well as the rupture areas scale with the seismic moment (Somerville et al., 1999). Using the source scaling of outer and inner fault parameters, we have developed characterized source model for predicting strong ground motions from future large earthquakes as a recipe (Irikura et al., 2004), Towards realistic ground motion prediction with dynamically-constraint parameters, we introduce (1) three-stage scaling of seismic moment and rupture area considering fault geometry, (2) stress drop distribution based on the multiple-asperity model, and (3) slip-velocity functions explaining surface and subsurface ruptures with difference fracture energy versus to the seismic moment. For (1), 3D dynamic simulations for both crack and asperity models naturally explain the circular-crack model with constant stress drop before fault width saturating the seismogenic zone, the L-model with increasing stress drop after the saturation of fault width, and the W-model with constant stress drop where the fault length becomes long enough. For (2), 3D dynamic simulations clarify the relationship between stress drop, slip, and number of asperities. Negative stress drop on the background area is proposed for the source model of large earthquakes with multiple asperities. For (3), we try to explain a paradox that the ground motions caused by subsurface rupture seem to be larger than the ones by surface rupture (Somerville, 2003) using slip-velocity functions considering larger fracture energy for surface rupture and smaller fracture energy for subsurface rupture, based on the dynamic simulations of recent large earthquakes.
DE: 7223 Seismic hazard assessment and prediction
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting