| Project/Area Number |
12680463
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Natural disaster science
|
|---|
| Research Institution | Yamaguchi University |
|---|
Principal Investigator |
KANAORI Yuji Yamaguchi Univ., Faculty of Science, Prof., 理学部, 教授 (60194883)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Tsuyoshi Yamaguchi Univ., Faculty of Engineering, Prof., 工学部, 教授 (10232307)
MIYATA Yuichiro Yamaguchi Univ., Faculty of Science, Assoc.Prof., 理学部, 助教授 (60253134)
|
|---|
| Project Period (FY) |
2000 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
|
|---|
| Keywords | Western Chugoku District / Tectonic basin / Fault movement / Fault rocks / Stress change / Structural analysis / Bedrock disaster / Reactivation |
|---|
| Research Abstract |
Seismic risk of active and geologic faults belonging to the NE-SW-trending West Yauneyama Lake Ohara fault system in Western Chugoku Distirct was evaluated, to mitigate seismic hazards that were induced by inland earthquakes. Topographical surveys and field mapping were performed for all the constituent active and geologic faults and characteristics and surface distributions of cataclasite and gauge zones accompanying those faults were clarified. Based on the structural analysis of the fault rocks, faults which constitute the West Yauneyama Lake Ohara fault system has inverted into the right-lateral motion from the left-lateral motion during the Middle Pliocene
Three destructive inland earthquakes of JMA magnitudes 5 to 6 have successively occurred in central-western Yamaguchi Prefecture dubbing the receipt fifteen years. Following the 1987 M=5.2 Central Yamaguchi Prefecture earthquake, the M=6.0 Suo-nada earthquake and the M=6.1 Northern Yamaguchi Prefecture earthquake in 1991 and 1997, respectively, were strong enough to cause moderate damage on houses. The epicenters of these three earthquakes were located along the active West Yauneyama-Lake Ohara fault system. We calculated the stress changes in the Coulomb Failure Function (CFF) induced by the three successive earthquakes, in order to evaluate seismic risk in and around this fault system. This calculation indicated that by the occurrence of these three earthquakes the stress increased in an approximately 10 to 30-km wide area along the Vest Yauneyama Lake Ohara fault system. The maximum stress increase was estimated to be 0.46 MPa at the Sakota-Ikumo fault. The stress also increased at the Eastern Mt. Mitsugatake fault. In contrast, the post-seismic stress decreased along the Tokusa-Jifuku, the Lake Ohara and the Shibuki faults. No stress change was produced on the Kikugawa fault
|
