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Reanalysis of seismic low velocity zones based on a pre-melting model.

Research Project

Project/Area Number 17H02951
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Solid earth and planetary physics
Research InstitutionThe University of Tokyo

Principal Investigator

Takei Yasuko  東京大学, 地震研究所, 教授 (30323653)

Project Period (FY) 2017-04-01 – 2020-03-31
Project Status Completed (Fiscal Year 2020)
Budget Amount *help
¥12,610,000 (Direct Cost: ¥9,700,000、Indirect Cost: ¥2,910,000)
Fiscal Year 2019: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
Fiscal Year 2018: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Keywordspremelting / 粘弾性 / 非弾性 / 地震波減衰 / 地震波低速度域 / アセノスフェア / プレメルティング / 岩石非弾性 / 部分溶融 / メルト / 界面 / フェーズフィールドモデル / 粒界 / 部分溶融岩石 / 粒界滑り / 低速度域
Outline of Final Research Achievements

Thermodynamic model of grain boundary developed for binary eutectic system predicts shows that the pre-melting occurrence can be expected in the Earth’s upper mantle. Based on the realistic volatile distribution and solidus profile obtained from a model of fractional decompression melting, we have shown that even when the oceanic upper mantle is melt free, geotherm sufficiently approaches the solidus at various plate ages, causing the lithosphere-asthenosphere system. We further clarified the quantitative effects of melt on anelasticity and developed a new anelasticity model which can be applied to a region with relatively large melt fraction (several percent). We also measured the impurity effects on anelasticity, and examined the similarities and differences between impurity effects and pre-melting effects.

Academic Significance and Societal Importance of the Research Achievements

本研究により、メルトが全くなくてもプレメルティングによってリソスフェアアセノスフェア構造が作られることが示された。この成果は、上部マントルにおける地震波低速度域の存在を、僅かな量のメルトしか存在しないとする地球化学的観測結果と整合的に理解することを可能にするという点で非常に大きな意義がある。また、地震波特性という高周波域から、粘性という長いタイムスケールまでの超広帯域での岩石物性を、室内実験データに基づいて予測した点にも、大きな学術的進歩がある。

Report

(4 results)
  • 2020 Final Research Report ( PDF )
  • 2019 Annual Research Report
  • 2018 Annual Research Report
  • 2017 Annual Research Report
  • Research Products

    (11 results)

All 2020 2019 2017 Other

All Int'l Joint Research (1 results) Journal Article (3 results) (of which Peer Reviewed: 3 results,  Open Access: 2 results) Presentation (7 results) (of which Int'l Joint Research: 6 results,  Invited: 2 results)

  • [Int'l Joint Research] ケンブリッジ大学(英国)

    • Related Report
      2018 Annual Research Report
  • [Journal Article] Application of a Premelting Model to the Lithosphere‐Asthenosphere Boundary2020

    • Author(s)
      Yamauchi Hatsuki、Takei Yasuko
    • Journal Title

      Geochemistry, Geophysics, Geosystems

      Volume: 21 Issue: 11 Pages: 125-125

    • DOI

      10.1029/2020gc009338

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Phase-Field Modeling of Grain Boundary Premelting2019

    • Author(s)
      Yasuko Takei
    • Journal Title

      Journal of Geophysical Research Solid Earth

      Volume: 124 Issue: 8 Pages: 8057-8076

    • DOI

      10.1029/2019jb017632

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Effects of Partial Melting on Seismic Velocity and Attenuation: A New Insight From Experiments2017

    • Author(s)
      Yasuko Takei
    • Journal Title

      Ann. Rev. Earth Planet. Sci.

      Volume: 45 Issue: 1 Pages: 447470-447470

    • DOI

      10.1146/annurev-earth-063016-015820

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed
  • [Presentation] Seismic discontinuity at lithosphere-asthenosphere boundary predicted from laboratory-based anelasticity model2020

    • Author(s)
      Hatsuki Yamauchi and Yasuko Takei
    • Organizer
      JPGU2020
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Rock anelasticity due to grain boundary preempting2019

    • Author(s)
      Y. Takei, H. Yamauchi, A. Tsunoda
    • Organizer
      JPGU-AGU joint meeting, Makuhari
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Rock anelasticity in the upper mantle2019

    • Author(s)
      Y. Takei
    • Organizer
      Symposiumin Honor of Y. Gueguen, ENS, Paris
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Experimental and theoretical approaches to grain boundary premelting: a possible origin of asthenosphere2019

    • Author(s)
      Y. Takei
    • Organizer
      EGU, Vienna, Austria
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 粒界熱力学モデルによるに成分共融系の粒界プレメルティング2019

    • Author(s)
      角田明博、武井康子、山内初希
    • Organizer
      JpGU 2019, 幕張
    • Related Report
      2018 Annual Research Report
  • [Presentation] Experimental study of the effects of partial melting on anelasticity: toward quantitative interpretations of seismic high attenuation2019

    • Author(s)
      H. Yamauchi, Y. Takei
    • Organizer
      JPGU-AGU joint meeting, Makuhari
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Grain boundary disordering just before partial melting2017

    • Author(s)
      Y. Takei
    • Organizer
      AGU fall meeting
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research

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Published: 2017-04-28   Modified: 2022-01-27  

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