2004 Fiscal Year Final Research Report Summary
Study on strong ground motion generated from dynamic rupture model
| Project/Area Number |
15510146
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Natural disaster science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MIYATAKE Takashi The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (60126183)
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| Co-Investigator(Kenkyū-buntansha) |
KUDO Kazuyosi The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (50012935)
YOSHIMI Masayuki National Institute of Advanced Industrial Science and Technology, Active Fault Research center, Researcher, 産業総合研究所, 研究員 (00358417)
NAKAMURA Hiromitu , 財団法人・鉄道総合研究所, 研究員
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| Project Period (FY) |
2003 – 2004
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| Keywords | Strong Ground Motion / Earthquake Source Process / Dynamic rupture model |
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| Research Abstract |
In near fault strong ground motion simulation, it is desired to construct physically reasonable source modeling. Nakamura and Miyatake (2000) have proposed an approximate expression of slip rate time function based on dynamic rupture model.
We also showed how to estimate the parameters of the above formula by using the slip-distribution or the kinematic information. Miyatake et al. (2003) have applied to the typical but simplified fault models with several asperities and discussed how to fix the parameters of the approximate expression. In this manuscript, in order to evaluate our approximate function, we apply it to the past earthquake, the 2001 Geiyo earthquake in order to evaluate our method. Comparison between the approximate time functions and those of dynamic model are satisfactory. The waveforms at nearfield stations generated from our approximate modeling fit those from dynamic model very well. Our functions based on dynamic model will help accurate simulation from a probable rupture scenario. We also investigate a dynamic rupture process of the earthquake and estimate the dynamic parameters. Firstly, the space-time distribution of slip of the earthquake, i.e., the kinematic model, was investigated by inverting the nearfield strong ground motion data and teleseismic waveform data. Secondly, we reconstruct a dynamic model in constraint with the above kinematic model. The distribution of Dc is also estimated from the inverted slip rate time functions (Mikumo et al., 2003) and found to be less than 70cm. We found that dynamic parameters are very heterogeneous. There exists two asperities. The peak stress drop on the first asperity is about 20MPa, and 10MPa on the second one. Very low or negative stress drop zone is found between two asperities. The strength excess, and fracture energy distribution are also heterogeneous.
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