Project/Area Number |
10554019
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Research Category |
Grant-in-Aid for Scientific Research (B).
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Allocation Type | Single-year Grants |
Section | 展開研究 |
Research Field |
固体地球物理学
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Research Institution | Nagoya University (2000) Kyoto University (1998-1999) |
Principal Investigator |
ANDO Masatala Science of school, Nagoya University, professor, 大学院・理学研究科, 教授 (80027292)
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Co-Investigator(Kenkyū-buntansha) |
YANAGIDANI Takashi Disaster Prevention Research Institute, Kyoto University, Assistant Professor, 防災研究所, 助教授 (00259128)
ISHII Hiroshi Earthquake Research Institute, The University of Tokyo, Professor, 地震研究所, 教授 (30004386)
OGASAWARA Hiroshi College of Science and engineering, Ritsumeikan University, Assitsant Professor, 理工学部, 助教授 (40213996)
TANANO Masao Graduate School of Science, Nagoya University, Assistant Professor, 大学院・理学研究科, 助教授 (90262849)
YAMAOKA Koshun Graduate school of Science, Nagoya University, Assistant Professor, 大学院・理学研究科, 助教授 (70183118)
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Project Period (FY) |
1998 – 2000
|
Keywords | Induced earthquake / Semi-controlled experiment / Stress |
Research Abstract |
To monitor both normal and shear strain on the fault where an M3 event is expected, an Ishii's borehole strainmeter and a 24-bit 25-Hz continuous data acquisition system were installed several meters from the fault underground in a gold mine in South Africa. Together with an accelerogram monitoring system with a dynamic range of 132 db and a sampling frequency of 15 kHz, in the last financial year, we got ready to monitor a whole life of an earthquake with good resolution and without clipping. However, the monitoring was postponed until this financial year because it took time to recover from an underground fire and a big tremor. Though we had to wait until the last September, we could make preliminary analysis of strain recordings after the last September using a data analysis software XMTS.We found that the observed earth tide had good agreement with that theoretically estimated, indicating that the strainmeter potentially detect as subtle changes as 10^<-9>, as originally designed. We are waiting for the start of mining, after which we expect to reveal a whole seismogenic processes, beginning with accumulation of stress followed by nucleation after a peak strength, together with a slip weakening or such post seismic effects as strength recovery.
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