2010 Fiscal Year Final Research Report
Internal Structure of the Median Tectonic Line fault zone revealed by analysis of continuous borehole core
| Project/Area Number |
20340136
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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 |
Geology
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| Research Institution | Tokyo Gakugei University |
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Principal Investigator |
FUJIMOTO Koichiro Tokyo Gakugei University, 教育学部, 准教授 (80181395)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGEMATSU Norio 産業技術総合研究所, 活断層地震研究センター, 主任研究員 (80308163)
WALLIS Simon 名古屋大学, 環境学研究科, 准教授 (30263065)
TAKAHASHI Miki 産業技術総合研究所, 活断層地震研究センター, 研究員 (40470033)
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| Co-Investigator(Renkei-kenkyūsha) |
TAKESHITA Toru 北海道大学, 理学系研究科, 教授 (30216882)
TAKAGI Hideo 早稲田大学, 教育・総合科学学術院, 教授 (60154754)
KOIZUMI Naoji 産業技術総合研究所, 活断層・地震研究センター, 研究グループ長 (00215154)
NAKAJIMA Takashi 産業技術総合研究所, 地質情報研究部門, 主任研究員
KANAGAWA Kyuichi 千葉大学, 理学部, 教授 (40185898)
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| Project Period (FY) |
2008 – 2010
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| Keywords | 中央構造線 / 断層帯内部構造 / 柱状図 / 変形の重複 / 変形条件 / 応力履歴 / 脆性-塑性遷移 |
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| Research Abstract |
A drill hole penetrates the Median Tectonic Line (MTL) at 473.9m depth which is the boundary between the Ryoke granitic rocks and the Sanbagawa metamorphic rocks. The internal structure of MTL fault zone was revealed by the drillcore samples, and has evolved through a series of faulting events under various temperature conditions from 450℃ to the surface. The evolution history of the fault zone can be divided into four stages based on the stress inversion analysis, and the fault zone experienced the brittle-plastic transition at the first stage during their evolution. A microstructure analysis revealed the stress state around the brittle-plastic transition zone. Analyses of altered minerals revealed the hydrothermal activities within the fault zone during the evolution. Raman spectroscopy of carbonaceous matter revealed the frictional heating along the MTL fault zone during the brittle faulting.
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