HR: 1330h
AN: S52A-0115    [PDF]
TI: Source Model of the 2002 Miyagi-Oki Interplate Earthquake (Mw=6.4) Obtained by Strong Ground Motion Simulation Using Empirical Green's Function Method
AU: * Suzuki, W
EM: suzuki@egmdpri01.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AU: Iwata, T
EM: iwata@egmdpri01.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AB: Previous studies show that strong motion records of crustal earthquakes can be successfully simulated using aftershock record as empirical Green's function with rectangular source model which is smaller than total fault size estimated from aftershock distribution. We call the area strong motion generation area (SMGA). It is also revealed that the SMGA corresponds to the asperity deduced by kinematic waveform inversion, and its size can be expected from scaling relation between the size of the asperity and the seismic moment. Asano et al. (2003) analyzed shallow intraslab earthquakes in the similar manner and derived that the size of SMGA is smaller than that expected for crustal earthquake of the same seismic moment, and the ratio of the derived and the expected sizes decreases with focal depth. This may implies that the deeper earthquake has the larger stress drop on the asperity. In November 3, 2002, an earthquake of $M_w=6.4$ (depth was about 45km) occurred in Miyagi-Oki region, north east of Japan, where high percentage of occurrence of interplate events is expected by the long term forecast. This event was thought to be interplate earthquake from moment tensor solution and aftershock distribution. We simulate broadband strong motion records of this interplate earthquake using empirical Green's function method proposed by Irikura (1986). Comparing observed and simulated waveforms, we derive the size and location of the SMGA by forward modeling. The obtained size of the SMGA is smaller than that expected from the relationship between the size and the seismic moment for crustal earthquakes, and is consistent with the relation among the size and the seismic moment and the depth derived from Asano et al. (2003). This result supports the idea that stress drop on the asperity mainly depend on its depth. We would like to thank K-NET and KiK-net for providing strong motion data, F-net for moment tensor solution, and JMA for information of hypocenter.
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2003 Fall Meeting