HR: 14:15h
AN: S42F-03 INVITED     [PDF]
TI: Recipe of Strong Ground Motion Prediction for Senario Earthquakes
AU: * Irikura, K
EM: irikura@egmdpri01.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AU: Miyake, H
EM: hiroe@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-0032 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
AU: Kamae, K
EM: kamae@kuca.rri.kyoto-u.ac.jp
AF: Research Reactor Institute, Kyoto University, 1010-1 Noda, Kumatori, Osaka, 590-0451 Japan
AU: Kawabe, H
EM: kawabe@kuca.rri.kyoto-u.ac.jp
AF: Research Reactor Institute, Kyoto University, 1010-1 Noda, Kumatori, Osaka, 590-0451 Japan
AU: Dalguer, L A
EM: dalguer@egmdpri01.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AB: From recent development of the waveform inversion analysis for estimating rupture process during large earthquakes, we have understood that strong ground motion is relevant to slip heterogeneity inside the source rather than the entire rupture area. The source characterization was made defining the entire rupture areas with a certain criterion in slip, and the asperities as regions that have two times slip as large as the average slip over the rupture area (Somerville et al., 1999). The important aspect from the source characterization is that the asperity areas as well as total rupture areas are expressed as a function of seismic moment. Based on the above scaling relationships, the source model for the prediction of strong ground motions is constructed by three kinds of parameters, outer, inner, and extra fault parameters. The outer fault parameters are defined as entire rupture area and total seismic moment. The inner fault parameters are defined as slip heterogeneity inside the source, i.e. area of asperities and stress drop on each asperity. We examined that strong motion generation areas approximately coincide with the asperity areas where stresses are strongly released (Miyake et al., 2001). A source model satisfying such characteristics is expressed as a dynamically-constrained multi-asperity model that is a extension a single-asperity model proposed by Das and Kostrov (1986). We have developed a recipe for predicting strong ground motions, which is to characterize the source model for scenario earthquakes. For the outer fault parameters, at first the total fault length is given as a sum of active fault segments. The fault width is related to the thickness of seismogenic zones. The entire source area is defined as a product of the length and width, and then the total seismic moment is derived following the empirical scaling relationship. For the inner fault parameters, the area of asperities is estimated from the scaling with the total seismic moment. Stress drop on each asperity is estimated by the ratio between the asperity and total rupture areas, and average stress drop over the entire rupture area. We found that the slip of the asperities is dynamically constraint depending on the number of the asperities. The pattern of rupture nucleation and termination as the extra fault parameters are related to geomorphology of active faults and plates. We have examined the validity of the earthquake sources constructed by the recipe, comparing simulated and observed ground motions for recent large earthquakes, such as the 1995 Kobe, 1999 Kocaeli, 1999 Chi-chi, 2000 Tottori, and other earthquakes.
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
DE: 7215 Earthquake parameters
DE: 7223 Seismic hazard assessment and prediction
SC: Seismology [S]
MN: 2003 Fall Meeting