1998 Fiscal Year Final Research Report Summary
Space-time distribution of near field seismic ground motions
| Project/Area Number |
09650528
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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 |
構造工学・地震工学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KIYONO Junji Kyoto Univ. Graduate School of Civil Eng. Assoc. Prof., 工学研究科, 助教授 (00161597)
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| Co-Investigator(Kenkyū-buntansha) |
TAKIMOTO Koichi Yamaguchi Univ. Faculty of Eng. Res. Assoc., 工学部, 助手 (50263794)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Earthquakes / Fault / Spatial Distribution / UD Component / Stress Drop / Impulsive Wave / Acceleration / Nonlinearity |
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| Research Abstract |
We here investigated near field ground motion induced by inland active faults. As the spatial distribution of earthquake ground motion near the fault is affected by the fault rupture mechanisms, FEM fault model is used to simulate near field ground motion. The fault model is two dimensional inverse fault. The possibility of existence of impulsive ground motion near the fault is also checked by using the FEM simulation. The descriptions of old manuscripts about the impulsive motions are collected and damage by the impulsive motions in 1995 Kobe earthquake is investigated. The results obtained by the study are as follows.
(1) There are many evidences that the structures are destroyed by the impulsive waves in Kobe earthquake.
(2) There are many descriptions that support the existence of the impulsive waves.
(3) The fault parameters such as stress drop and critical displacement have a strong effect to the acceleration amplitude of the up-down component.
(4) The large amplitude of the up-down component occurs by the rapid stop of the rupture.
(5) The nonlinear effect of the surrounded soil of the fault sometimes amplifies the amplitude of the surface ground motion.
(6) In case that the S-wave velocity of the surface layer is smaller, long duration pulse is appeared.
(7) Even if the seismic wave contains large amplitude, high-frequency components, the components can not be recorded by the servo-type accelerograph.
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