| Project/Area Number |
07454100
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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 |
固体地球物理学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SUYEHIRO Kiyoshi Univ.of Tokyo, Ocean Research Inst, Prof., 海洋研究所, 教授 (20133928)
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| Co-Investigator(Kenkyū-buntansha) |
TAIRA Asahiko Univ.of Tokyo, Ocean Research Inst., Prof., 海洋研究所, 教授 (50112272)
TOKUYAMA Hidekazu Univ.of Tokyo, Ocean Reseach Inst., Assoc.Prof., 海洋研究所, 助教授 (10107451)
HINO Ryota Tohoku Univ., Fac of Science, Res Assoc., 理学部, 助手 (00241521)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1996: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1995: ¥3,600,000 (Direct Cost: ¥3,600,000)
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| Keywords | oceanic crust / OBS / upper mantle / 自然地震 / 伊豆小笠原 |
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| Research Abstract |
The aim of this study was to image the uppermantle heterogeneity beneath an oceanic island arc system using ocean bottom seismographic recordings of teleseismic events by conventional instrumants and by newly developed long-period long-term instrument, amd to geologically interpret the results. We have imaged the low-Q zone above the subducting slab in the Izu-Ogasawara src system and a deep aseismic subducting plate beneath the Solomons arc system using conventional instrumants. The subducting aseismic slab was detected by using teleseismic P-wave traveltime relativeresidual patterns. However, the predominant frequencies of 1 Hz or less are beyond the useful range of conventional OBS(ocean bottom seismograph), so that we developed a new OBS equipped with 1-Hz sensor and 4 GB data capacity for about 3-month recording. We have not yet acquired data with this system yet.
The Izu-Ogasawara oceanic arc crust was interpreted to have been produced in an early stage of subduction when relatively hot environement existed. This environment produced Boninites with ample water content and it is interpreted that the re-melting of the lower crust formed the granitic crust.
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