2013 Fiscal Year Final Research Report
Geofluid investigated from seismic waves
| Project Area | Geofluids: Nature and dynamics of fluids in subduction zones |
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| Project/Area Number |
21109002
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| Research Category |
Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
MATSUZAWA Toru 東北大学, 理学(系)研究科(研究院), 教授 (20190449)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Aitaro 東京大学, 地震研究所, 准教授 (20359201)
OKADA Tomomi 東北大学, 大学院理学研究科, 准教授 (30281968)
NAKAJIMA Junichi 東北大学, 大学院理学研究科, 准教授 (30361067)
YAMAMOTO Mare 東北大学, 大学院理学研究科, 助教 (30400229)
ISHIKAWA Masahiro 横浜国立大学, 環境情報研究院, 教授 (70232270)
KOSUGA Masahiro 弘前大学, 理工学研究科, 准教授 (90142835)
TAKAHASHI Tsutomu 独立行政法人海洋研究開発機構, 地球内部ダイナミクス領域, 研究員 (90435842)
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| Co-Investigator(Renkei-kenkyūsha) |
ARIYOSHI Keisuke 独立行政法人海洋研究開発機構, 地震津波・防災研究プロジェクト, 研究員 (20436075)
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| Project Period (FY) |
2009-07-23 – 2014-03-31
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| Keywords | 地殻流体 / 地震発生過程 / マグマ生成過程 |
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| Research Abstract |
We installed a dense seismograph array around Naruko volcano, and found a conspicuous low-velocity zone, above which seismicity was very active. We conjectured that this low-velocity zone showed the existence of water there based on the comparison with an electric conductivity distribution and elastic wave speeds estimated from rock experiments. We obtained similar results from seismic observation data around Wakayama. We found that seismic waves were strongly attenuated in these low-velocity zones. We also investigated seismic velocity in the descending oceanic plates and found evidences for the existence of water in seismically active regions. All these results indicate that water is playing an important role in generation of earthquakes in subduction zones.
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