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沈み込み帯に持ち込まれる堆積物の不均質性とデコルマゾーン形成時の挙動

Publicly Offered Research

Project AreaNew perspective of great subduction-zone earthquakes from the super deep drilling
Project/Area Number 22107507
Research Category

Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

Allocation TypeSingle-year Grants
Review Section Science and Engineering
Research InstitutionJapan Agency for Marine-Earth Science and Technology

Principal Investigator

山本 由弦  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 (10435753)

Project Period (FY) 2010 – 2011
Project Status Completed (Fiscal Year 2011)
Budget Amount *help
¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2011: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2010: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywords沈み込み帯 / 付加体 / デコルマゾーン / 圧密試験 / セメント
Research Abstract

本研究は,プレート沈み込み帯に持ち込まれる堆積物中にデコルマゾーンが形成されるメカニズムの解明を目指すものである.室戸沖南海付加体では,粘土鉱物が弱くセメントされた層準にデコルマゾーンが発達することが報告されている.弱くセメントされた泥質岩は,繰り返し載荷に対して脆弱であるという性質があるため,デコルマゾーン形成メカニズムにはプレート境界特有の有効応力変動(地震波や間隙水圧の伝播などに起因)が鍵を握っていると考えた.本研究では,この有効応力変動を再現できる圧密試験機(等方圧密)を開発した.試験機は,最大封圧20MPa,封圧変動を最速5Hz与えられる仕様である.
本年度は,主に房総半島の海溝斜面堆積物(堆積年代は約2.8Ma)を用いて試験を行った.試験は,通常の圧密試験(封圧変動なし)によって得られた降伏圧密強度までいったん封圧を上昇させ,そこから任意の周波数・応力変動を与えた.等方圧密方式を採用しているため,理論的には組織の異方性には変化が起こらないはずである.実際,通常の圧密試験後の試料と試験前の試料では,異方性に違いは見られなかった.ところが,封圧変動を作用させると地層面に平行な方向に面構造がより発達する.試料を地層面に対して垂直および水平に整形しても同じ結果が確認されたことから,異方性は堆積構造異方性がより強調される傾向にあることが判明した.これらの結果は,上載荷重による圧密に比べ,有効応力変動による組織改編および物性変化が劇的なものであることを示している.プレート沈み込み帯のような変動帯では,これらを評価することが必要である.また,デコルマゾーンが形成されるメカニズムの解明をめざし,昨年行われたExp.333で採取された,デコルマゾーンの材料物質というべきセメント層準を採取した.今後これら試料を用いてデコルマ形成の再現試験を行う予定である.

Report

(2 results)
  • 2011 Annual Research Report
  • 2010 Annual Research Report
  • Research Products

    (28 results)

All 2012 2011 2010

All Journal Article (9 results) (of which Peer Reviewed: 9 results) Presentation (19 results)

  • [Journal Article] Fabric-based criteria to distinguish tectonic from sedimentary melanges in the Shimanto accretionary complex2012

    • Author(s)
      Yuzuru Yamamoto
    • Journal Title

      Tectonophysics

      Volume: (In press) Pages: 65-73

    • DOI

      10.1016/j.tecto.2011.10.018

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Silica diagenesis and its effect on interplate seismicity in cold subduction zones2012

    • Author(s)
      Jun Kameda
    • Journal Title

      Earth and Planetary Science Letters

      Volume: 317-318 Pages: 136-144

    • DOI

      10.1016/j.epsl.2011.11.041

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Relationship between magnetic fabrics and shear directions in melange within the Miyama Formation, Shimanto accretionary complex, Japan2012

    • Author(s)
      Tetsuya Tokiwa
    • Journal Title

      Tectonophysics

      Volume: (In press) Pages: 53-64

    • DOI

      10.1016/j.tecto.2011.11.001

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Systematic variation of fabric and physical properties in mass transfer deposits in the Ursa region, Northern Gulf of Mexico2011

    • Author(s)
      Yuzuru Yamamoto
    • Journal Title

      Advances in Natural and Technological Hazards Research

      Volume: 31 Pages: 649-658

    • DOI

      10.1007/978-94-007-2162-3_58

    • ISBN
      9789400721616, 9789400721623
    • Related Report
      2011 Annual Research Report 2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Systematic development of submarine slope failures at subduction margins : fossil record of accretion-related slope failure in the Miocene Hota Accretionary Complex, Central Japan2011

    • Author(s)
      Yuzuru Yamamoto
    • Journal Title

      Advances in Natural and Technological Hazards Research

      Volume: 31 Pages: 355-364

    • DOI

      10.1007/978-94-007-2162-3_32

    • ISBN
      9789400721616, 9789400721623
    • Related Report
      2011 Annual Research Report 2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Records of submarine landslides in subduction input recovered by IODP Expedition 322, Nankai Trough, Japan2011

    • Author(s)
      Yujin Kitamura
    • Journal Title

      Advances in Natural and Technological Hazards Research

      Volume: 31 Pages: 659-690

    • DOI

      10.1007/978-94-007-2162-3_59

    • ISBN
      9789400721616, 9789400721623
    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Principal horizontal stress orientations prior to the 2011 Mw 9.0 Tohoku-Oki, Japan, earthquake in its source area2011

    • Author(s)
      Lin, W., Saito, S., Sanada, Y., Yamamoto, Y., Hashimoto, Y., Kanamatsu, T
    • Journal Title

      Geophysical Research Letters

      Volume: 38 Issue: 7 Pages: n/a-n/a

    • DOI

      10.1029/2011gl049097

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Costa Rica Seismogenesis Project (CRISP) : sampling and quantifying input to the seismogenic zone and fluid output2011

    • Author(s)
      Expedition 334 Scientists
    • Journal Title

      IODP Preliminary Report

      Volume: 334

    • DOI

      10.2204/iodp.pr.334.2011

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Smectite swelling in the Miura-Boso accretionary prism : Possible cause for incipient decollement zone formation2010

    • Author(s)
      Kameda Jun
    • Journal Title

      Tectonophysics

      Volume: 484 Pages: 156-167

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Presentation] Spatial and time variations in stress state in the Costa Rica subduction margin, IODP Expedition 3342012

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      Penrose conference, GSA
    • Place of Presentation
      Castelvecchio Pascoli, Italy
    • Year and Date
      2012-03-30
    • Related Report
      2011 Annual Research Report
  • [Presentation] Architecture of young and non-metamorphosed onland accretionary wedge in the Miura and Boso peninsulas, central Japan : an analogs of the Nankai subduction margin2012

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      International Conference on a New Perspective of Great Earthquakes along Subduction Zones
    • Place of Presentation
      Kochi, Japan
    • Year and Date
      2012-02-27
    • Related Report
      2011 Annual Research Report
  • [Presentation] Preliminary results of stress and strain analyses in Costa Rica subduction margin, IODP Expedition 3342012

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      International Conference on a New Perspective of Great Earthquakes along Subduction Zones
    • Place of Presentation
      Kochi, Japan
    • Year and Date
      2012-02-27
    • Related Report
      2011 Annual Research Report
  • [Presentation] Preliminary results of stress and strain analyses, IODP Expedition 334, Costa Rica Seismogenesis Project (CRISP)2011

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      AGU
    • Place of Presentation
      San Francisco, USA
    • Year and Date
      2011-12-06
    • Related Report
      2011 Annual Research Report
  • [Presentation] Systematic development of submarine slope failures at subduction margins : fossil record of accretion-related slope failure in the Miocene Hota Accretionary Complex, Central Japan2011

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      IGCP 5^<th> International Symposium
    • Place of Presentation
      Kyoto, Japan
    • Year and Date
      2011-10-25
    • Related Report
      2011 Annual Research Report
  • [Presentation] Systematic variation of fabric and physical properties in mass transfer deposits in the Ursa region, Northern Gulf of Mexico2011

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      IGCP 5^<th> International Symposium
    • Place of Presentation
      Kyoto, Japan
    • Year and Date
      2011-10-24
    • Related Report
      2011 Annual Research Report
  • [Presentation] Stress state analyses at the subduction input site, Site C0012, Nankai Subduction Zone, using anelastic strain recovery. IODP Exp.3222011

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      IODP Exp.322 post-cruise meeting
    • Place of Presentation
      Barcelona, Spain
    • Year and Date
      2011-09-26
    • Related Report
      2011 Annual Research Report
  • [Presentation] Costa Rica浸食型沈み込み帯における応力および構造解析:IODP Expedition 334の速報2011

    • Author(s)
      山本由弦
    • Organizer
      日本地質学会118大会
    • Place of Presentation
      水戸市(茨城大学)
    • Year and Date
      2011-09-10
    • Related Report
      2011 Annual Research Report
  • [Presentation] Along strike migration of intermittent submarine landslides at subduction margins : a geologic evidence2011

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      JPGU Meeting
    • Place of Presentation
      Chiba, Japan
    • Year and Date
      2011-05-25
    • Related Report
      2011 Annual Research Report
  • [Presentation] Exp.322航海のSite C0012における沈み込む直前の堆積物と基盤岩のASR応力解析2011

    • Author(s)
      山本由弦
    • Organizer
      日本地球惑星科学連合大会
    • Place of Presentation
      千葉市幕張
    • Year and Date
      2011-05-25
    • Related Report
      2011 Annual Research Report
  • [Presentation] 三浦・房総半島の付加体・被覆層システム2011

    • Author(s)
      山本由弦
    • Organizer
      日本地球惑星科学連合大会
    • Place of Presentation
      千葉市幕張
    • Year and Date
      2011-05-23
    • Related Report
      2011 Annual Research Report
  • [Presentation] Three-dimensional stress orientation in the basement basalt at the subduction input site, Nankai Subduction Zone, using anelastic strain recovery (ASR) data, IODP NanTroSEIZE Site C0012.2010

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      AGU
    • Place of Presentation
      Moscone Convention Center, San Francisco, U.S.A.
    • Year and Date
      2010-12-14
    • Related Report
      2010 Annual Research Report
  • [Presentation] Onland accretionary wedge in the Miura and Boso peninsulas, central Japan : one of the best analogs of modern subduction-accretion system2010

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      GSA Tectonic crossroads Conference
    • Place of Presentation
      Middle East Technical University, Ankara, Turkey
    • Year and Date
      2010-10-08
    • Related Report
      2010 Annual Research Report
  • [Presentation] Formation processes of chaotic rock-units during primary accretion processes : Liquefaction and mass transport deposits in the Miura Boso Accretionary prism, central Japan2010

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      GSA Tectonic crossroads Conference
    • Place of Presentation
      Middle East Technical University, Ankara, Turkey
    • Year and Date
      2010-10-08
    • Related Report
      2010 Annual Research Report
  • [Presentation] Thickening of tectonic melanges due to clay-mineral transition in 2-4 km depth in subduction zone : Hota accretionary complex, central Japan2010

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      GSA Tectonic crossroads Conference
    • Place of Presentation
      Middle East Technical University, Ankara, Turkey
    • Year and Date
      2010-10-05
    • Related Report
      2010 Annual Research Report
  • [Presentation] 南海および陸上の付加体をつなげる三浦・房総半島の付加体・被覆層システム2010

    • Author(s)
      山本由弦
    • Organizer
      日本地質学会
    • Place of Presentation
      富山大学(富山県)
    • Year and Date
      2010-09-19
    • Related Report
      2010 Annual Research Report
  • [Presentation] Decollement zone thickening due to clay-mineral transition in 2-4 km buried subduction zone : Hota accretionary complex, central Japan2010

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      WPGM
    • Place of Presentation
      Taipei International Convention Center, Taipei, Taiwan
    • Year and Date
      2010-06-23
    • Related Report
      2010 Annual Research Report
  • [Presentation] 沈み込み帯の深度2-4kmにおける堆積物変形と粘土鉱物組成変化:房総半島中部中新統保田層群2010

    • Author(s)
      山本由弦
    • Organizer
      日本地球惑星科学連合大会
    • Place of Presentation
      幕張メッセ(千葉県)
    • Year and Date
      2010-05-25
    • Related Report
      2010 Annual Research Report
  • [Presentation] Fabric variation and primary heterogeneity of subduction input, off Kii Peninsula : Preliminary results from IODP Expedition 3222010

    • Author(s)
      Yuzuru Yamamoto
    • Organizer
      日本地球惑星科学連合大会
    • Place of Presentation
      幕張メッセ(千葉県)
    • Year and Date
      2010-05-23
    • Related Report
      2010 Annual Research Report

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Published: 2010-08-23   Modified: 2018-03-28  

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