2000 Fiscal Year Final Research Report Summary
Comparative study of surface displacement and deformation due to Hyogoken-nanbu earthquake
| Project/Area Number |
10440143
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Osaka City University |
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Principal Investigator |
HIRANO Masahige Osaka City Univ.Fac.Literature, Prof., 文学部, 教授 (00047177)
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| Co-Investigator(Kenkyū-buntansha) |
MITAMURA Muneki Osaka City Univ.Fac.Sci., Assoc.Prof., 理学部, 助教授 (00183632)
HADA Shigeki Kobe Univ.Res.Inst.Higher Education, Prof., 大学教育研究センター, 教授 (40036554)
ISHII Takayuki Osaka Kyoiku Univ.Dept.Education, Prof., 教育学部, 教授 (40045159)
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| Project Period (FY) |
1998 – 2000
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| Keywords | comparative study / surface offset / Hyogoken-nanbu earthquake / horizontal displacement / landslide / sediment compaction / tectonic movement |
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| Research Abstract |
Surface displacement and deformation due to Hyogoken-nanbu earthquake reflect the tectonic development of Rokko Mountains. Systematic offsets are recognized on south-western extension of geologic faults in Mt.Rokko. Precise description of them and comparison with those in Awaji Island were attempted. The displacement and deformation are compared with Iwateken-hokubu earthquake and the others. Horizontal displacement of bench marks by the earthquake was analysed in comparison with dislocation model, and a shallow fault was distinguished form a deep one, though some related problems will be overcome in future. Vertical displacement and dilatation are related, and sediment compaction or buckling of basement rock can be detected. Landslide or housing damage shows preferred orientation and local concentration, and this concerns fault and local large acceleration. Equivalent horizontal acceleration was obtained using such structures with horizontal joints as tomb stones. Direction and magnitude of equivalent horizontal acceleration were obtained, and the result was compared with those by Tottoriken-seibu earthquake. Occurrence of an earthquake concerns the stress difference induced from Poison's number in subsurface area in laterally constraint condition. The number increases from 2.5 near land surface to 5 or a little more in the source area. The fact is in harmony with previous results on rock strength or the stress difference just before the Hyogoken-nanbu earthquake.
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