2015 Fiscal Year Final Research Report
Development of a Method to Identify the Heterogeneous Subsurface Structure based on the Horizontal-to-Vertical Spectral Ratio of Microtremors
| Project/Area Number |
25420577
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Building structures/Materials
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
KAWASE Hiroshi 京都大学, 防災研究所, 教授 (30311856)
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | 拡散波動場 / 微動 / 水平上下スペクトル比 / 不整形地盤構造 / 方位依存性 / 数値解析 / 方位依存パワー |
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| Outline of Final Research Achievements |
As an index to estimate the directional dependency of the Horizontal-to-Vertical spectral ratio of microtremors (MHVR), we defined an index called "directional dependent power". The index was found to be effective from the analysis of the observed data that has been accumulated over the years, as well as newly obtained ones.
At one of the sites that showed clear directional dependence, we calculated the numerical MHVRs according to the new interpretation of MHVRs based on the diffuse field assumption by using a two-dimensional subsurface structure model. The target area was the area surrounding the Onahama strong motion observation station of the strong-motion earthquake observation network in port areas in Japan where the heterogeneity of the subsurface structure was suggested from the directional dependence of spatially distributed observed microtremor MHVRs. As a result, the numerical MHVRs showed a fairly good match to the observed ones.
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| Free Research Field |
地震工学
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