HR: 11:50h
AN: S52A-07    [Abstracts]
TI: Characterized Source Modeling of Surface and Subsurface Faulting for Strong Motion Prediction
AU: * Irikura, K
EM: irikura@egmdpri01.dpri.kyoto-u.ac.jp
AF: Kyoto University, Yoshida-Hommachi, Sakyo-ku, Kyoto, 606-0011 Japan
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: Dalguer, L A
EM: ldalguer@moho.sdsu.edu
AF: Department of Geological Science, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1020 United States
AU: Matsushima, S
EM: matsushima@shimz.co.jp
AF: Ohsaki Research Institute, Fukoku Seimei Bldg., 2-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo, 100-0011 Japan
AU: Dan, K
EM: kazuo.dan@shimz.co.jp
AF: Ohsaki Research Institute, Fukoku Seimei Bldg., 2-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo, 100-0011 Japan
AU: Sato, T
EM: Toshiaki.sato@shimz.co.jp
AF: Ohsaki Research Institute, Fukoku Seimei Bldg., 2-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo, 100-0011 Japan
AU: Kagawa, T
EM: kagawa@geor.or.jp
AF: Geo Research Institute, 4-3-2 Itachibori, Nishi-ku, Osaka, 550-0012 Japan
AU: Mai, P M
EM: mai@sed.ethz.ch
AF: Institute of Geophysics, ETH Zurich, ETH Hoenggerberg, Zurich, 8093 Switzerland
AU: Somerville, P G
EM: Paul_Somerville@urscorp.com
AF: URS Corporation, 566 El Dorado Street, Pasadena, CA 91101-2560 United States
AU: Pitarka, A
EM: Arben_pitarka@urscorp.com
AF: URS Corporation, 566 El Dorado Street, Pasadena, CA 91101-2560 United States
AU: Song, S G
EM: seisgoo@pangea.stanford.edu
AF: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, CA 94305-2215 United States
AU: Beroza, G C
EM: beroza@pangea.stanford.edu
AF: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, CA 94305-2215 United States
AB: In order to improve current approaches for near-source ground motion prediction, we construct a source characterization for surface and subsurface earthquakes based on the dynamic rupture simulation. We attempt to explain the paradox that ground motions caused by subsurface rupture seem to be larger than those of surface rupture at a period of 1 second (Somerville, 2003). Recent studies of kinematic source models show larger stress drop for subsurface asperities and smaller stress drop for surface asperities (e.g., Kagawa et al., 2004). Our dynamic rupture simulation shows that the fracture energy is gradually increasing from the subsurface- and surface-rupture earthquakes as a function of the stress intensity factor (e.g., Mai et al., 2005). Using the differences of stress drop, the scaling slope of the fracture energy Gc and stress intensity factors, we interpret that asperities of surface-rupture earthquakes require larger Dc than subsurface-rupture earthquakes for a given effective stress, which is defined as a peak-to-peak stress in the time domain. We construct Kostrov-like slip-velocity functions as functions of effective stress and slip-weakening distance for asperities of surface and subsurface faulting. The surface rupture earthquakes have lower maximum slip-velocity and its peak time is larger due to the smaller effective stress and larger fracture energy. The subsurface rupture earthquakes have larger maximum slip-velocity and its peak time is shorter due to the larger effective stress and smaller fracture energy. We performed strong ground motion simulation using the characterized source model which consists of asperities and background area. The physics-based slip-velocity time functions for the models are examined in comparison with the observed records and simulated motions for the 1992 Landers earthquake (Mw 7.2), a large surface faulting event, and the 1997 Kagoshima earthquake (Mw 6.0), an event that occurred on a previously unknown structure (undefined-subsurface faulting). Near-source ground motion simulations show the applicability of the proposed slip-velocity functions explaining the ground motion differences between the surface and subsurface faulting at a period of 1 second.
DE: 7209 Earthquake dynamics (1242)
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7215 Earthquake source observations (1240)
SC: Seismology [S]
MN: Fall Meeting 2005