1998 Fiscal Year Final Research Report Summary
Estimation of site effects using strong ground motion network data
| Project/Area Number |
09680445
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
IWATA Tomotaka DPRI, Kyoto Univ., Research Associate, 防災研究所, 助手 (80211762)
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| Project Period (FY) |
1997 – 1998
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| Keywords | K-NET / site effects / strong motion data / SP convert wave / Q-value / geometrical attention / Green's function |
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| Research Abstract |
First, I constructed strong motion data base in Kansai area. Data were provided by Kyoshin-net, CEORKA, and temporal strong motion observation group for Kobe. Also, I collected geological and geophysical underground structure information of the sites. Using these data base, we tried to separate site and source factors and Q-values by the inversion method (Iwata and Irikura, 1988). Obtained Q-values coincide with those by the previous studies. For estimating Q-values, we can obtain the stable Q-values with using data set of only rock and hard-soil sites. Q-values from vertical component of S-waves are consistent with those from horizontal S-wave component and this shows that vertical component of S-waves travel as S-waves in the crust. Site factors of vertical component of S-waves are similar to those of vertical component of P-wave part and this concludes that the vertical component of S-waves is mainly composed by P-waves.
Secondly, we estimated site factors in and around large earthquake disaster area in Kobe during the 1995 Hyogoken Nanbu earthquake. Even in the large disaster area, site factors are different among the sites and this shows only superficial layer amplification effects can not explain the large disaster in Kobe.
Using K-net data, we also obtained source rupture processes of the 1997 Kagoshimaken-Hokuseibu earthquakes using a small shock data as a empirical Green's function.
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