Evaluation of coseismic fluid and melt processes in earthquake faults by geochemical and petrological analyses

• Project/Area Number: 16H04066
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: ISHIKAWA Tsuyoshi 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(高知コア研究所), 研究所長 (30270979)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000); Fiscal Year 2019: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2018: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2017: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2016: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000)
• Keywords: 地震 / 断層 / 地球化学 / 流体岩石相互作用 / 摩擦溶融

Outline of Final Research Achievements

Fault rocks formed by earthquake slip provide useful information for understanding coseismic physicochemical processes within the fault zones. This study was aimed at developing new methods for evaluating fluid-rock interactions and frictional melting, both of which are considered to enhance the earthquake slip in subduction zone, based on geochemical analyses of the fault rocks. The new methods enabled not only to evaluate coseismic fluid-rock interactions at high temperatures (>350 deg. C) but also to assess the effects from aseismic-slip-induced fluid processes at low temperatures. It was shown that lithium and boron isotopes can be effective tracers of fluid processes in the faults. Geochemical modeling for the evaluation of frictional melting was also successfully developed.

Academic Significance and Societal Importance of the Research Achievements

摩擦熱による流体圧上昇（熱圧化：thermal pressurization）や摩擦溶融は、沈み込み帯の地震時において断層強度を著しく低下させることで断層の破壊伝播を促進し、巨大津波の発生にもつながると考えられている。しかしながら、前者にあっては地震時に存在していた流体が地震後に断層から散逸すること、後者にあっては溶融の痕跡が断層の変質により失われることで、地震断層においてそれらの履歴を評価するのは困難であった。本研究は、断層岩の化学分析に基づく新手法を提供することでそれらの定量的評価を可能とし、津波を誘起する大きな断層滑りの履歴の把握など、防災・減災上有用な情報の取得につながる。

Research Products

• [Journal Article] Postseismic fluid discharge chemically recorded in altered pseudotachylyte discovered from an ancient megasplay fault: an example from the Nobeoka Thrust in the Shimanto accretionary complex, SW Japan (2019)
  • Author(s): Hasegawa Ryota, Yamaguchi Asuka, Fukuchi Rina, Hamada Yohei, Ogawa Nobuhiro, Kitamura Yujin, Kimura Gaku, Ashi Juichiro, Ishikawa Tsuyoshi
  • Journal Title: Progress in Earth and Planetary Science Volume: 6 Issue: 1 Pages: 36-36
  • DOI: 10.1186/s40645-019-0281-2
  • Peer Reviewed / Open Access
• [Journal Article] Equatorial Pacific seawater pCO2 variability since the last glacial period (2019)
  • Author(s): Kubota Kaoru、Yokoyama Yusuke、Ishikawa Tsuyoshi、Sagawa Takuya、Ikehara Minoru、Yamazaki Toshitsugu
  • Journal Title: Scientific Reports Volume: 9 Issue: 1 Pages: 13814-13814
  • DOI: 10.1038/s41598-019-49739-0
  • Peer Reviewed / Open Access
• [Journal Article] The State of Stress on the Fault Before, During, and After a Major Earthquake (2019)
  • Author(s): Brodsky, E.E., Mori, J. J., Anderson, L., Chester, F. M., Conin, M., Dunham, E. M., Eguchi, N., Fulton, P., Hino, R., Hirose, T., Ikari, M., Ishikawa, T., Jeppson, T., Kano, Y., Kirkpatrick, J., Kodaira, S., Lin, W., Nakamura, Y., Rabinowitz, H, Regalla, C., Remitti, F., Rowe, C., Saffer, D., Saito, S. et al.
  • Journal Title: Annual Review of Earth and Planetary Sciences Volume: 48 Issue: 1 Pages: 49-74
  • DOI: 10.1146/annurev-earth-053018-060507
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Geochemical analysis unveils frictional melting process in a subduction zone fault (2019)
  • Author(s): Ishikawa, T. and Ujiie, K.
  • Journal Title: Geology Volume: 47 Issue: 4 Pages: 343-346
  • DOI: 10.1130/g45889.1
  • Peer Reviewed
• [Journal Article] Sequential chemical separation of Sr, Nd and Pb from geological samples using multi-step extraction column chromatography (2018)
  • Author(s): 若木重行、川合達也、永石一弥、石川剛志
  • Journal Title: JAMSTEC Report of Research and Development Volume: 27 Issue: 0 Pages: 1-12
  • DOI: 10.5918/jamstecr.27.1
  • NAID: 130007506144
  • ISSN: 1880-1153, 2186-358X
  • Year and Date: 2018-09-01
  • Peer Reviewed / Open Access
• [Journal Article] A Rapid and Precise Determination of Boron Isotope Ratio in Water and Carbonate Samples by Multiple Collector ICP-MS (2018)
  • Author(s): Tanimizu, M.、Nagaishi, K.、Ishikawa, T.
  • Journal Title: Analytical Sciences Volume: 34 Issue: 6 Pages: 667-674
  • DOI: 10.2116/analsci.18SBP05
  • NAID: 130007395544
  • ISSN: 0910-6340, 1348-2246
  • Year and Date: 2018-06-10
  • Peer Reviewed / Open Access
• [Journal Article] Tectono-seismic characteristics of faults in the shallow portion of an accretionary prism (2018)
  • Author(s): Hirono, T. and Ishikawa, T.
  • Journal Title: Tectonophysics Volume: 724-725 Pages: 179-194
  • DOI: 10.1016/j.tecto.2018.01.014
  • Peer Reviewed
• [Journal Article] Isotope analysis of nanogram to sub-nanogram sized Nd samples by total evaporation normalization thermal ionization mass spectrometry (2018)
  • Author(s): Wakaki, S. and Ishikawa, T.
  • Journal Title: INTERNATIONAL JOURNAL OF MASS SPECTROMETRY Volume: 424 Pages: 40-48
  • DOI: 10.1016/j.ijms.2017.11.014
  • Peer Reviewed
• [Journal Article] Rapid decline in pH of coral calcification fluid due to incorporation of anthropogenic CO2 (2017)
  • Author(s): Kubota Kaoru、Yokoyama Yusuke、Ishikawa Tsuyoshi、Suzuki Atsushi、Ishii Masao
  • Journal Title: Scientific Reports Volume: 7 Issue: 1 Pages: 1-9
  • DOI: 10.1038/s41598-017-07680-0
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Precise and accurate analysis of deep and surface seawater Sr stable isotopic composition by double-spike thermal ionization mass spectrometry (2017)
  • Author(s): Wakaki, S., Obata, H., Tazoe, H. and Ishikawa, T.
  • Journal Title: Geochemical Journal Volume: 51
  • NAID: 130006837066
  • Peer Reviewed
• [Journal Article] Influence of laser parameters on isotope fractionation and optimisation of lithium and boron isotope ratio measurements using laser ablation-multiple Faraday collector-inductively coupled plasma mass spectrometry (2016)
  • Author(s): Kimura J.-I., Chang Q., Ishikawa T., and Tsujimori T.
  • Journal Title: Journal of Analytical Atomic Spectrometry Volume: 31 Issue: 11 Pages: 2305-2320
  • DOI: 10.1039/c6ja00283h
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Kodiak付加体のアルバイトを伴う黒色断層岩の起源：地球化学分析からの制約 (2019)
  • Author(s): 石川 剛志, 山口 飛鳥
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] コディアック付加体のプレート境界断層岩の形成に寄与した流体の起源 (2019)
  • Author(s): 石川 剛志, 山口 飛鳥
  • Organizer: 2019年度日本地球化学会年会
• [Presentation] Origin of frictional melt in the Jurassic accretionary complex of the Mino Belt on the basis of trace element and isotope analysis (2019)
  • Author(s): 尾澤 ちづる、石川 剛志、氏家 恒太郎
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] Geochemical evidence for source materials of frictional melt: an example from the pseudotachylyte in the Jurassic accretionary complex, central Japan (2019)
  • Author(s): Chizuru Ozawa, Tsuyoshi Ishikawa and Kohtaro Ujiie
  • Organizer: American Geophysical Union Fall Meeting 2019
  • Int'l Joint Research
• [Presentation] Origin of fluids involved in paleo-plate-boundary decollement in the Kodiak accretionary complex (2018)
  • Author(s): Tsuyoshi Ishikawa and Asuka Yamaguchi
  • Organizer: American Geophysical Union Fall Meeting 2018
  • Int'l Joint Research
• [Presentation] Chemical characteristics and source of the fluid involved in the black fault rocks in the Kodiak accretionary complex (2018)
  • Author(s): Tsuyoshi Ishikawa and Asuka Yamaguchi
  • Organizer: Japan Geoscience Union Meeting 2018
  • Int'l Joint Research
• [Presentation] Origin of frictional melt in the Jurassic accretionary complex of the Mino-Tamba Belt, central Japan on the basis of trace element and isotope analyses (2018)
  • Author(s): Chizuru Ozawa, Tsuyoshi Ishikawa and Kohtaro Ujiie
  • Organizer: American Geophysical Union Fall Meeting 2018
  • Int'l Joint Research
• [Presentation] Kodiak付加体のアルバイトを伴う黒色断層岩形成に寄与した流体の起源 (2018)
  • Author(s): 石川 剛志, 山口 飛鳥
  • Organizer: 日本地質学会第125年学術大会（2018札幌大会）
• [Presentation] 微量元素からひもとく摩擦熔融物の起源 (2018)
  • Author(s): 尾澤 ちづる, 氏家 恒太郎, 石川 剛志
  • Organizer: 日本地質学会第125年学術大会（2018札幌大会）
• [Presentation] 和歌山県日高川層群に発達する巨大分岐断層の滑り挙動の解明 (2018)
  • Author(s): 小川 丈彰, 石川 剛志, 金木 俊也, 廣野 哲朗
  • Organizer: 日本地球惑星科学連合2018年大会
• [Presentation] Characterization of frictional melting processes in subduction zone faults by trace element and isotope analyses (2017)
  • Author(s): Ishikawa, T. and Ujiie, K.
  • Organizer: American Geophysical Union Fall Meeting 2017
  • Int'l Joint Research
• [Presentation] Geochemical anomaly in ancient subduction boundary fault: Trench-parallel heterogeneity (2017)
  • Author(s): Ogawa, T., Ishikawa, T., Kaneki, S. and Hirono, T.
  • Organizer: American Geophysical Union Fall Meeting 2017
  • Int'l Joint Research
• [Presentation] 断層岩の地球化学分析による沈み込み帯断層の摩擦溶融履歴評価 (2017)
  • Author(s): 石川 剛志、氏家 恒太郎
  • Organizer: 日本地球惑星科学連合 2017年大会
• [Presentation] 断層岩の地球化学分析による沈み込み帯断層の摩擦溶融履歴評価 (2017)
  • Author(s): 石川剛志、氏家恒太郎、川合達也、永石一弥
  • Organizer: 2017年度日本地球化学会第64回年会
• [Presentation] 断層岩の微細組織に沿った主成分・微量元素およびSr同位体分析 (2017)
  • Author(s): 川合達也、永石一弥、石川剛志、氏家恒太郎
  • Organizer: 2017年度日本地球化学会第64回年会
• [Presentation] Evaluation of frictional melting on the basis of trace element analyses of fault rocks (2016)
  • Author(s): Tsuyoshi Ishikawa, Kohtaro Ujiie
  • Organizer: American Geophysical Union Fall Meeting 2016
  • Place of Presentation: サンフランシスコ（アメリカ合衆国）
  • Year and Date: 2016-12-13
  • Int'l Joint Research
• [Presentation] 微小量断層岩の微量元素・同位体比の包括分析：1.マイクロサンプリングと主成分・微量元素分析 (2016)
  • Author(s): 石川剛志, 川合達也, 永石一弥, 氏家恒太郎, 亀田純, 三島稔明
  • Organizer: 2016年度日本地球化学会 第63回年会
  • Place of Presentation: 大阪市立大学杉本キャンパス（大阪市住吉区）
  • Year and Date: 2016-09-16
• [Presentation] 微小量断層岩の微量元素・同位体比の包括分析：２. Li・B・Sr・Nd・Pb 同位体分析 (2016)
  • Author(s): 石川剛志, 永石一弥, 川合達也, 若木重行, 氏家恒太郎, 亀田純, 三島稔明
  • Organizer: 2016年度日本地球化学会 第63回年会
  • Place of Presentation: 大阪市立大学杉本キャンパス（大阪市住吉区）
  • Year and Date: 2016-09-16
• [Presentation] ホウ素・リチウム同位体を用いた日本海溝プレート境界断層浅部における流体岩石相互作用の評価 (2016)
  • Author(s): 石川剛志・永石一弥・松岡淳・亀田純・James Sample
  • Organizer: 日本地質学会第123年学術大会
  • Place of Presentation: 日本大学文理学部キャンパス（東京都世田谷区）
  • Year and Date: 2016-09-11
• [Presentation] Boron and lithium isotope constraints on fluid-rock interactions in the shallow megathrust at the Japan Trench (2016)
  • Author(s): Tsuyoshi Ishikawa, Jun Matsuoka, Kazuya Nagaishi, Jun Kameda, James Sample
  • Organizer: Goldschmidt Conference 2016
  • Place of Presentation: パシフィコ横浜（神奈川県横浜市）
  • Year and Date: 2016-06-28
  • Int'l Joint Research
• [Presentation] Evaluation of coseismic physicochemical processes in fault zones based on geochemical analyses of fault rocks (2016)
  • Author(s): Tsuyoshi Ishikawa
  • Organizer: Japan Geoscience Union Meeting 2016
  • Place of Presentation: 幕張メッセ国際会議場（千葉県千葉市）
  • Year and Date: 2016-05-23
  • Int'l Joint Research / Invited
• [Remarks] 堆積物中の有孔虫化石の高精度分析から読み解く大気・海洋間の炭素交換
  • URL: http://www.jamstec.go.jp/kochi/j/news/20191031.html
• [Remarks] 高知コア研究所 - 国立研究開発法人 海洋研究開発機構（JAMSTEC）
  • URL: http://www.jamstec.go.jp/kochi/
• [Remarks] 高知コア研究所 - 国立研究開発法人 海洋研究開発機構（JAMSTEC）
  • URL: http://www.jamstec.go.jp/kochi/j/index.html