HR: 0800h
AN: S21A-0202    [Abstracts]
TI: Broadband Ground Motion Validation of the Great 1923 Kanto Earthquake Using the New Image of the Philippine Sea Slab and Integrated 3D Velocity-Structure Model
AU: * Miyake, H
EM: hiroe@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Koketsu, K
EM: koketsu@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Kobayashi, R
EM: reiji@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Tanaka, Y
EM: ystanaka@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Ikegami, Y
EM: ikegami@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Ikegami, Y
EM: ikegami@eri.u-tokyo.ac.jp
AF: CRC Solutions Corp., 2-7-5 Minamisuna, Koto-ku, Tokyo, 136-8581 Japan
AB: The Tokyo metropolitan area is under constant threat of strong ground motions from future plate-boundary earthquakes along the subducting Philippine Sea slab. The Great 1923 Kanto earthquake is one of the most disastrous earthquakes in the last century killing about 105,000 people. We here upgrade the broadband ground motion simulation of the 1923 event using a physics-based source model, realistic velocity-structure model, and efficient computational tool. The source and 3D velocity-structure models will be validated by the comparison of the synthetic and observed waveforms at the University of Tokyo and detailed distributions of seismic intensities. The source process was inferred from strong-motion, teleseismic, and geodetic data with the new geometry of the Philippine Sea slab by Sato et al. (2005). The 3D velocity-structure model beneath the Tokyo metropolitan area has been constructed by integrating refraction, reflection, borehole, microtremor, and gravity data as well as ground motion spectra (e.g., Tanaka et al., 2005). In this model, the deepest point of the basement surface is located at a depth of 4 km. We first performed low-frequency ground motion simulation using these models and the finite element method with a voxel mesh developed by Koketsu et al. (2004). The western basin edge complicated the wave propagation and the excited long-period motions within the basin were found to continue for several minutes. Since high-frequency components are essential for seismic intensity measurement, we then simulate high-frequency ground motions using the stochastic Green's function method and a pseudo-dynamic source model (Guatteri et al., 2004) based on the slip distribution of Kobayashi and Koketsu (2005). The simulated broadband ground motion is expected to validate the distribution of asperities in the source model along the shallower plate geometry, where the eastern major asperity is located closer toward downtown Tokyo than in the previous models.
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7215 Earthquake source observations (1240)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005