| Project/Area Number |
17K18962
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Social systems engineering, Safety engineering, Disaster prevention engineering, and related fields
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| Research Institution | National Institute of Advanced Industrial Science and Technology |
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Principal Investigator |
Cho Ikuo 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 主任研究員 (10328560)
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| Co-Investigator(Kenkyū-buntansha) |
横田 俊之 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 研究グループ長 (40358312)
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| Project Period (FY) |
2017-06-30 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
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| Keywords | 微動アレイ探査 / 表面波探査 / ノイズ補正 / 表層地質 / 浅部速度構造 / 平均S波速度 / 地震工学 / 地盤工学 / 自然災害 / 地震 |
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| Outline of Final Research Achievements |
We performed microtremor observation with a miniature seismic array with radius less than 1 m at exactly the same site as the previous surface-wave-exploration site in order to evaluate the accuracy of a miniature microtremor array method for a depth range from 1 to 10 m. The experimental site was set on an artificial ground at Itako City, Ibaraki, Japan. From the comparison between those phase velocities, we found that the shallower limit of the analyzable depth range for a miniature microtremor array method with radius of 0.6 m lies at about 1 to 2 m in depth. However, it was also revealed that, since the excitation modes of the surface wave were different between those methods, the exact comparison of the phase-velocity dispersion curves was difficult. For this reason, we planned and completed additional research, (i) to develop two kinds of approaches to inferring an S-wave velocity structure and (ii) to correct the incoherent noise for identifying phase velocities.
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| Academic Significance and Societal Importance of the Research Achievements |
表面波探査（SW）法による位相速度分散曲線の比較に基づく極小微動アレイ（MMA）の浅い側の解析限界は、観測仕様、観測機材に依存するものの、本検討の場合は深さ1～2m程度と考えられた。また、それぞれの分散曲線に基づくS波速度構造の比較によれば、SW法とMMA法は、逆解析精度の範囲内で同様な結果を与える。上記の結果に基づけば、探査対象が深さ2m以上ならば、微動の極小アレイは、表面波探査に必要となる観測機材や時間を削減できる代替法となり得る。現実には地盤の相違によるばらつきがあると考えられるが、本研究により、MMA法の新たな需要を創出するための探査限界のオーダーを把握できたと考える。
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