HR: 0800h
AN: S31A-1032    [Abstracts]
TI: Application of the 'Recipe for Strong Ground Motion Evaluation' to the 2003 Tokachi-oki, Japan, Earthquake
AU: * Morikawa, N
EM: morikawa@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki, 306-0006 Japan
AU: Aoi, S
EM: aoi@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki, 306-0006 Japan
AU: Honda, R
EM: ryou@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki, 306-0006 Japan
AU: Senna, S
EM: senna@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki, 306-0006 Japan
AU: Hayakawa, Y
EM: hayakawa@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki, 306-0006 Japan
AU: Fujiwara, H
EM: fujiwara@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki, 306-0006 Japan
AB: The National Research Institute for Earth Science and Disaster Prevention has carried on the special research project 'National Seismic Hazard Mapping Project of Japan'. In this project, strong ground motion evaluations for scenario earthquakes have been carried out based on the 'Recipe for strong ground motion evaluation' proposed by Irikura et al. (2004). Here we simulate strong ground motions during the 2003 Tokachi-oki earthquake (Mw=8.0) by applying the 'Recipe', and examine its validity. A simplified source model consists of some rectangular-shaped asperities on a fault plane is constructed following the method in the 'Recipe'. A 3D velocity structure model in and around Hokkaido, which is the target area for the simulation, is also constructed based on boreholes, reflection and refraction surveys, and geological data. Waveforms are calculated by the hybrid Green's function method (Kamae et al., 1998). We use the 3D finite-difference method and the stochastic Green's function method for low ($<$ 0.2 Hz) and high frequency content, respectively. As an overall feature, the peak ground velocity and seismic intensity distributions of simulated strong ground motions agree well with the observed ones. However, some problems become clear. The first is the underestimations in the frequency range of 0.2-1 Hz at sites located on deep basins. This may be a lack in the evaluation on the effects of 3D structure in the calculations using the stochastic Green's function. The second is the overestimations in high frequency range ($>$ 2 Hz) at sites located on back-arc side. This may be caused by the existence of low-Q zone beneath the volcanic front, which is not considered in this simulation. In addition, the non-linear site effects also should be considered in strong motion evaluations, especially for soft soil sites near source region.
DE: 7223 Seismic hazard assessment and prediction
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2004 AGU Fall Meeting