| Project/Area Number |
13450413
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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 |
資源開発工学
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| Research Institution | Tohoku University |
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Principal Investigator |
ASANUMA Hiroshi Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (50250717)
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| Co-Investigator(Kenkyū-buntansha) |
MORIYA Hirokazu Tohoku University, Graduate School of Engineering, Lecturer, 大学院・工学研究科, 講師 (60261591)
NIITSUMA Hiroaki Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (90108473)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥8,800,000 (Direct Cost: ¥8,800,000)
Fiscal Year 2002: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2001: ¥6,100,000 (Direct Cost: ¥6,100,000)
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| Keywords | TFC / 3DTFC / Downhole Double 3C detector / Crosshole seimsic / Artificial Fracture / Leaky Surface Wave / Hodogram / Time-frequency representation / 3次元TFC法 / 坑井内弾性波計測 / 地下き裂 / 散乱波 / 回折波 / き裂波 |
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| Research Abstract |
(a)Field Studies: Crosshole seismic measurement at Tohoku University Higashi-Hachimantai Field was carried out. Downhole airgun was used as a seismic source and signals transmitted through artificially pressurized fracture was recorded. The state of pressurization, location of source and detector were changed.
(b)Analysis by the TFC/3DTFC method: The recorded signals in the field experiment were analyzed by the time-frequency coherency (TFC) and by the 3D-TFC methods. Some coherent components including direct arrivals, reflected phase and unknown coherent waves were discriminated.
(c)Interpretation: Possible physics to generate coherent waves from pressurised fracture was investigated using theory of elastic wave. It has been concluded that leaky guided waves propagating along fracture is the most possible origin of detected coherent waves with lower velocity and highly correlated to pressurization.
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