Details of the Researcher

PHOTO

Sando Sawa
Section
Graduate School of Science
Job title
Assistant Professor
Degree

  • 博士（理学）（東北大学）

  • 修士（理学）（東北大学）

e-Rad No.
90972430

Research History 5

  • 2024/04 - Present
    Tohoku University　Institute for Excellence in Higher Education　Assistant professor

  • 2022/10 - Present
    Tohoku University　Graduate School of Science Department of Earth Science　Assistant Professor

  • 2022/04 - 2022/09
    Tokyo University of Agriculture and Technology　Institute of Engineering Division of Advanced Mechanical Systems Engineering　JSPS Postdoctoral Research Fellow

  • 2020/04 - 2022/03
    JSPS Postdoc fellow (DC2)

  • 2018/04 - 2022/03
    The International Joint Graduate Program in Earth and Environmental Sciences, Tohoku University Research Fellow

Education 3

  • Tohoku University　Graduate School of Science　Department of Earth Science, Doctoral course

    2019/04 - 2022/03

  • Tohoku University　Graduate School of Science　Department of Earth Science, Master course

    2017/04 - 2019/03

  • Tohoku University　Faculty of Science　Division of GeoEnvironmental Science

    2013/04 - 2017/04

Professional Memberships 4

  • The Japan Society of High Pressure Science and Technology

  • European Geosciences Union

  • American Geophysical Union

  • Japan Geoscience Union

Research Interests 4

  • Experimental seismology

  • Phase-field simulation

  • Mineral rheology

  • Rock Physics

Research Areas 1

  • Natural sciences / Solid earth science / Rock Physics

Awards 1

  1. Outstanding Student Presentation Award

    2019/06　Japan Geoscience Union　Grain Size Dependency of Olivine-Spinel Phase Transformational Mechanism Responsible for Deep-focus Earthquakes

Papers 10

  1. Induced Earthquakes Inhibited by Shear Thickening Fluid

    Lu Wang, Yusuke mukuhira, Yasuo YABE, Sando Sawa, Jun Muto

    2025/07/28

    DOI： 10.22541/essoar.175370190.02133888/v1 　

  2. The brittle-plastic transition in quartz-albite aggregates: New insights from shear deformation experiments at mid-to-lower crustal depth conditions

    Miho Furukawa, Berend Antonie Verberne, Sando Sawa, Hiroyuki Nagahama, Miki Takahashi, Oliver Plümper, Jun Muto

    2025/02/12

    DOI： 10.22541/essoar.173939620.02997850/v1 　

  3. Magnitude distribution during phase transformation faulting: Implication for deep-focus earthquakes

    Sando Sawa, Julien Gasc, Nobuyoshi Miyajima, Alexandre Schubnel, Marie Baïsset, Jun Muto

    2024/07/31

    DOI： 10.22541/au.172243928.81251816/v1 　

  4. Effect of faceting on olivine wetting properties Peer-reviewed

    Yongsheng Huang, Takayuki Nakatani, Sando Sawa, Guoji Wu, Michihiko Nakamura, Catherine McCammon

    American Mineralogist　108　(12)　2244-2259　2023/12/01

    Publisher: Mineralogical Society of America

    DOI： 10.2138/am-2022-8808 　

    ISSN： 0003-004X

    eISSN： 1945-3027

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    Abstract Grain-scale pore geometry primarily controls the fluid distribution in rocks, affecting material transport and geophysical response. The dihedral angle (θ) in the olivine-fluid system is a key parameter determining pore fluid geometry in mantle wedges. In the system, curved and faceted olivine-fluid interfaces define θ, resulting in faceted-faceted (FF), faceted-curved (FC), and curved-curved (CC) angles. The effect of faceting on θ under various pressure and temperature (P-T) conditions and fluid compositions, however, has not been constrained, and mineralogical understanding remains unresolved. This study evaluated facet-bearing θ and their proportions in olivine-multicomponent aqueous fluid systems. Our results show that 1/3 of olivine-fluid θ are facet-bearing angles, regardless of the P-T conditions and fluid composition. Faceting produces larger dihedral angles than CC angles. The grain boundary plane (GBP) distribution reveals that the GBPs of faceted interfaces at triple junctions have low Miller index faces ({100}, {010}, and {101}). The misorientation angle/axis distributions of adjacent grain pairs are in accord with a theoretical distribution of random olivine aggregate. Moreover, the calculation of the FF angles for adjacent grain pairs with low Miller index GBPs reproduces measured angle values based on the olivine crystal habit. Therefore, our study suggests that the FF angle is strongly affected by olivine crystallography. The presence of faceting increases θ and a critical fluid fraction (φc) for percolation, lowering permeability. In the mantle wedge, where olivine crystallographic preferred orientation (CPO) is expected owing to corner flow, increasing the FF angle proportion with associated changes in fluid pore morphology will lead to permeability anisotropy, and controlling the direction of the fluid flow, and it will result in geophysical anomalies such as seismic wave attenuation and high electrical conductivity.

  5. A split Hopkinson pressure bar for experimental investigation of dynamic pulverization under very high strain rates Peer-reviewed

    Eranga Gayanath Jayawickrama, Takuma Sekiguchi, Jun Muto, Sando Sawa, Hiroyuki Nagahama, Yoshio Kono, Kyung-Oh Bae, Hyung-Seop Shin

    Review of Scientific Instruments　94　(9)　2023/09/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0151448 　

    ISSN： 0034-6748

    eISSN： 1089-7623

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    Off-fault damage or pulverized rocks found in large-scale strike–slip faults are of great interest in earthquake research. In order to experimentally investigate rock pulverization, we developed a split Hopkinson pressure bar with compact dimensions and high-speed imaging. The developed experimental setup is capable of generating very high strain rates up to 1320 s−1 with the satisfaction of stress equilibrium, which are essential to reproduce the dynamic pulverization observed in nature and obtain dynamic stress–strain responses accurately. High-speed imaging revealed that cracks initiate and propagate along the grain boundaries at very high speeds, while the dynamic stress–strain response suggested that energy dissipated into the fracture increases with stronger impacts. In addition, we show that the apparatus is capable of producing particle size distributions partly similar to those in naturally pulverized rocks of large-scale strike–slip faults. Thus, our developed system with compact dimensions opens new ways to understand the dynamics of the rock pulverization in off-fault regions of large-scale strike–slip faults.

  6. Modeling of olivine-spinel phase transformation of germanate olivine (Mg2GeO4) by using the phase-field method Peer-reviewed

    Sando Sawa, Jun Muto, Hiroyuki Nagahama

    Physics of the Earth and Planetary Interiors　341　107060-107060　2023/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.pepi.2023.107060 　

    ISSN： 0031-9201

  7. Enhancement of ductile deformation in polycrystalline anorthite due to the addition of water Peer-reviewed

    Junichi Fukuda, Jun Muto, Sanae Koizumi, Sando Sawa, Hiroyuki Nagahama

    Journal of Structural Geology　156　104547-104547　2022/03

    Publisher: Elsevier BV

    DOI： 10.1016/j.jsg.2022.104547 　

    ISSN： 0191-8141

  8. Localized Deformation of Lawsonite During Cold Subduction Peer-reviewed

    R. Shiraishi, J. Muto, A. Tsunoda, S. Sawa, A. Suzuki

    Journal of Geophysical Research: Solid Earth　127　(2)　2022/02

    Publisher: American Geophysical Union (AGU)

    DOI： 10.1029/2021jb022134 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  9. Strain-induced partial serpentinization of germanate olivine with a small amount of water Peer-reviewed

    Sando Sawa, Nobuyoshi Miyajima, Jun Muto, Hiroyuki Nagahama

    American Mineralogist　106　(11)　1789-1796　2021/11/01

    Publisher: Mineralogical Society of America

    DOI： 10.2138/am-2021-7735 　

    ISSN： 0003-004X

    eISSN： 1945-3027

  10. Strain localization bands in fine-grained aggregates of germanate olivine and pyroxene deformed by a Griggs type apparatus Peer-reviewed

    Sando Sawa, Jun Muto, Nobuyoshi Miyajima, Rei Shiraishi, Masanori Kido, Hiroyuki Nagahama

    International Journal of Rock Mechanics and Mining Sciences　144　104812-104812　2021/08

    Publisher: Elsevier {BV}

    DOI： 10.1016/j.ijrmms.2021.104812 　

    ISSN： 1365-1609

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Presentations 17

  1. フェーズフィールド法によるゲルマニウムかんらん石の変形条件下での相転移挙動モデリング Invited

    澤燦道, 武藤潤, 長濱裕幸

    日本地球惑星科学連合2024　2024/05/26

  2. マントルウェッジの CO2 交代作用による滑石生成プロセスとすべり挙動に対する実験的制約

    沖野峻也, 岡本敦, 喜多倖子, 澤燦道, 武藤潤

    日本地質学会　2023/09

  3. b values dependency on olivine grain size in phase transformation faulting: Implication for deep-focus earthquakes

    Sando Sawa, Nobuyoshi Miyajima, Julien Gasc, Alexandre Schubnel, Marie Baïsse, Jun Muto

    International Joint Workshop on Slow-to-Fast Earthquakes 2023　2023/09

  4. Brittle-ductile transition of quartz-feldspar aggregates simulated by shear deformation experiments

    Miho Furukawa, Berend A. Verberne, Sando Sawa, Jun Muto, Miki Takahashi, Hiroyuki Nagahama

    WRI-17　2023/08/21

  5. Sintering dense and homogeneous Labradorite polycrystal aggregates using hot pressing and slip casting

    Yukiko Kita, Jun Muto, Norio Shigematsu, Sando Sawa

    Earth, Sea and Sky VIII　2023/05/31

  6. Dislocation creep in cataclasite with seismic slip zone in an exhumed accretionary complex

    Yoshitaka Hashimoto, Mako Kawaji, Jun Muto, Hiroaki Yokoyama, Sando Sawa

    2023/05/25

  7. Brittle behavior of Lawsonite under the conditions of cold subduction zone

    白石 令, 武藤 潤, 角田 明博, 澤 燦道, 鈴木 昭夫

    日本地球惑星科学連合2023　2023/05/24

  8. Experimental study on the brittle-plastic transition in quartz-feldspar aggregates

    2023/05/21

  9. フェーズフィールド法によるゲルマニウムかんらん石の相転移シミュレーション

    澤燦道, 武藤潤, 長濱裕幸

    日本機械学会第 35 回計算力学講演会　2022/11/16

  10. Microstructure evolution of olivine-spinel phase transformation under differential stress for deep-focus earthquakes by phase field method

    S. SAWA, J. MUTO, H. NAGAHAMA

    ICOTOM 19　2021/03

  11. Grain size dependency of the phase transformational faulting mechanism responsible for deep-focus earthquakes

    S. SAWA, N. MIYAJIMA, J. MUTO, H. NAGAHAMA

    AGU fall meeting　2019/12

  12. Grain Size Dependency of Ge-Olivine/Spinel on Phase Transformational Faulting Mechanism for Deep-focus Earthquakes

    S. SAWA, J. MUTO, N. MIYAJIMA, H. NAGAHAMA

    GeoMünster　2019/09

  13. Strain Localization Bands Developed in Experimentally Created Fine-grained Aggregates

    S. SAWA, J. MUTO, N. MIYAJIMA, H. NAGAHAMA

    Workshop on Deep Volatile Cycling in the Earth　2019/06

  14. Grain Size Dependency of Olivine-Spinel Phase Transformational Mechanism Responsible for Deep-focus Earthquakes

    S. SAWA, J. MUTO, N. MIYAJIMA, H. NAGAHAMA

    JpGU　2019/05

  15. Study of Mechanism Responsible for Deep-focus Earthquakes by a Griggs Type Piston Cylinder Apparatus

    S. SAWA, N. MIYAJIMA, J. MUTO, H. NAGAHAMA

    The 59th High Pressure Conference of Japan　2018/11

  16. Mechanism of Olivine-spinel Transformation and Microstructural Development under Differential Stress by Phase Field Method

    S. SAWA, J. MUTO, H. NAGAHAMA

    EGU General Assembly　2018/04

  17. Phase transformation Mechanism Responsible for Deep-focus Earthquakes by the Multi-Phase-Field Methods

    S. SAWA, M. KIDO, R. SHIRAISHI, J. MUTO, H. NAGAHAMA

    JpGU-AGU Joint Meeting　2017/05

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Research Projects 4

  1. 破壊実験と断層調査から解明する地震のエネルギー散逸過程

    長濱 裕幸, 武藤 潤, 奥村 聡, 河野 義生, 澤 燦道

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(B)

    Institution: 東北大学

    2024/04/01 - 2027/03/31

  2. 実験―シミュレーション―データ同化から明らかにする下部地殻延性せん断帯の時間発展

    澤 燦道

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 若手研究

    Institution: 東北大学

    2023/04 - 2026/03

  3. 岩石の組織・破壊シミュレーションから見るプレートテクトニクスの起源

    澤 燦道

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: 東京農工大学

    2022/04/22 - 2025/03/31

  4. 高温高圧実験とフェーズフィールド法による相転移断層形成と深発地震の発生機構の解明

    澤 燦道

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: 東北大学

    2020/04/24 - 2022/03/31

    More details Close

    沈み込むスラブ深部（410-660 km）で発生する地震を深発地震と呼ぶが、その発生メカニズムに関していまだ不明な点は多い。岩石変形実験や地球物理的観測によって、かんらん石がより高密度なスピネル相に相転移する際に地震が発生するという相転移断層運動モデルが、深発地震の断層の動きはじめを担うと有力視されている。しかしながら、相転移に大きな影響を与える粒径の効果は明らかになっていない。 そこで、かんらん石のアナログ物質である細粒なゲルマニウムかんらん石多結晶体（数ミクロン）と粗粒な多結晶体（数百ミクロン）を合成した。多結晶体内の亀裂（断層）発生を検出するためのAEセンサーをつけたGriggs型固体圧変形試験機を用いて変形実験を行った。結果、細粒な多結晶体ではスピネルはオリビンの粒界で主に相転移し、粗粒な多結晶体では粒内で主に相転移していた。細粒な多結晶体と粗粒な多結晶体の両方で亀裂発生が検出されたが、そのタイミングや大きさが異なっていた。この違いが地球物理的観測によって得られるパラメータに影響している可能性がある。現在この結果に関して論文投稿準備中である。 相転移断層運動モデルにおいて、変形が局所化するほどの急激な相転移がどのように進むのか、いまだ統一的な見解は存在していない。そこで相転移組織の時間発展を計算できるPhase Field法を用いて、相転移のシミュレーションを行った。塑性ひずみを考慮すると、スピネルへの相転移は急激に進んでいくが、塑性ひずみを考慮しないと相転移の速度が徐々に遅くなることが明らかになった。塑性ひずみがスピネルへの相転移を促進し、変形の局所化につながっている可能性がある。現在この結果は論文としてまとめ、国際誌で査読中である。