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Earthquake cycle simulation considering viscoelastic relaxation aiming for understanding and forecasting earthquake occurrence

Research Project

Project/Area Number 16K17789
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Solid earth and planetary physics
Research InstitutionThe University of Tokyo (2019)
National Institute of Advanced Industrial Science and Technology (2016-2018)

Principal Investigator

Ohtani Makiko  東京大学, 地震研究所, 助教 (80759689)

Project Period (FY) 2016-04-01 – 2020-03-31
Project Status Completed (Fiscal Year 2019)
Budget Amount *help
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Keywords地震発生サイクル / 粘弾性 / 等価体積力法 / H行列法 / EnKF法 / 粘弾性媒質 / 境界要素法 / データ同化 / 粘性率 / クーロン応力 / 三次元粘性構造 / 応力場 / 断層すべり / 地震
Outline of Final Research Achievements

For realizing 3D earthquake cycle simulation considering the non-linear viscoelastic relaxation, I constructed a fast-computation method. I used the body-force method that takes into account the viscoelastic response using the stress-strain Green’s function in the elastic medium and applied the H-matrices method that compresses dense matrices. The computational amount is reduced from O(N2) to O(NlogN) by applying the H-matrices method, where N is the number of discretized cells of the viscoelastic region. Using the body-force method, I evaluated the Coulomb stress change (ΔCFF) by the viscoelastic deformation after the 2018 Hokkaido Eastern Iburi earthquake. I also developed the method of estimating the viscoelastic structure under the ground from the viscoelastic deformation data after large earthquakes using a data-assimilation method.

Academic Significance and Societal Importance of the Research Achievements

本研究では、巨大地震発生の理解と予測を目指し、実際の巨大地震発生領域を対象として地下の粘弾性領域における応力緩和の影響を考慮した大規模地震発生サイクルシミュレーションを実施するために、計算手法の開発を行った。本手法は比較的小さい計算コストで、断層の三次元幾何形状、非線形粘弾性や不均質な粘性構造等複雑な地下の状態をある程度反映することができる。また実際にシミュレーションを実施するのに必要となる地下の粘弾性構造を、モデルとデータの両方に依拠するデータ同化手法によって推定する手法の枠組みを作成した。今後本手法を拡張すれば、地震発生後の余効変動に含まれる各成分の切り分けにも役立つと考えられる。

Report

(5 results)
  • 2019 Annual Research Report   Final Research Report ( PDF )
  • 2018 Research-status Report
  • 2017 Research-status Report
  • 2016 Research-status Report
  • Research Products

    (8 results)

All 2019 2018 2017

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

  • [Journal Article] Nucleation of Characteristic Earthquakes in Simulated Cycles Involving Deep Huge Slow Slip Events2019

    • Author(s)
      Ohtani Makiko、Kame Nobuki、Nakatani Masao
    • Journal Title

      Journal of Geophysical Research: Solid Earth

      Volume: 124 Issue: 2 Pages: 1822-1837

    • DOI

      10.1029/2018jb016156

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Seismic potential around the 2018 Hokkaido Eastern Iburi earthquake assessed considering the viscoelastic relaxation2019

    • Author(s)
      Makiko Ohtani、Kazutoshi Imanishi
    • Journal Title

      Earth, Planets and Space

      Volume: 71 Issue: 1 Pages: 57-57

    • DOI

      10.1186/s40623-019-1036-4

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] EnKFによる粘弾性変形および粘性構造の推定 ー 数値実験2019

    • Author(s)
      大谷真紀子
    • Organizer
      日本地震学会2019年度秋季大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] Stress change due to the large earthquake along the Nankai Trough, SW Japan, in a viscoelastic medium2018

    • Author(s)
      Makiko Ohtani, Kazuro Hirahara
    • Organizer
      AOGS2018
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] Application of H-matrices method to the evaluation of the post-seismic relaxation2018

    • Author(s)
      大谷真紀子,平原和朗
    • Organizer
      2018年度地球惑星連合大会
    • Related Report
      2018 Research-status Report
  • [Presentation] 018年北海道胆振東部地震による石狩低地東縁断層帯のΔCFFの時間変化2018

    • Author(s)
      大谷真紀子、今西和俊
    • Organizer
      地震学会2018年度秋季大会
    • Related Report
      2018 Research-status Report
  • [Presentation] 粘弾性媒質中の応力計算におけるH行列法適用2017

    • Author(s)
      大谷真紀子・平原和朗
    • Organizer
      日本地震学会2017年秋季大会
    • Related Report
      2017 Research-status Report
  • [Presentation] Application of H-matrices method to the calculation of stress field in a viscoelastic medium2017

    • Author(s)
      Makiko Ohtani and Kazuro Hirahara
    • Organizer
      2017AGU Fall meeting
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research

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Published: 2016-04-21   Modified: 2021-02-19  

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