KEISHI OKAZAKI

Last Updated :2026/06/10

Affiliations, Positions
Graduate School of Advanced Science and Engineering, Associate Professor
Web Site
https://sites.google.com/view/keishiokazaki-jamstec/home
E-mail
keishiokazakihiroshima-u.ac.jp
Self-introduction
I study rheological properties (fracture, friction, crystal plasticity) of rocks and minerals, especially fault zone materials and metamorphic rocks (e.g., hydrated mantle, altered oceanic crust and sediments), and how they evolve during metamorphic reactions to understand the mechanism of normal/slow earthquakes in subduction zones.

Basic Information

Major Professional Backgrounds

  • 2022/04/01, Hiroshima University, Graduate School of Advanced Science and Engineering, Associate Professor
  • 2022/04/01, Japan Agency for Marine-Earth Science and Technology, Kochi Institute for Core Sample Research, x-star, Visiting Senior Researcher
  • 2018/04/01, 2018/09/30, Tohoku University, Adjunct Lecturer
  • 2016/10/01, 2022/03/31, Japan Agency for Marine-Earth Science and Technology, Kochi Institute for Core Sample Research, x-star, Researcher
  • 2016/10/01, 2016/12/31, Brown University, Department of Earh, Environmental and Planetary Sciences, Visiting Scientist
  • 2014/04/01, 2016/09/30, Brown University, Department of Earh, Environmental and Planetary Sciences, Postdoctoral Research Associate
  • 2013/04/01, 2014/03/31, Brown University, Department of Earh, Environmental and Planetary Sciences, Visiting Scholar
  • 2012/04/01, 2013/03/31, Hirhoshima University, Graduate School of Science,Department of Earth and Planetary Systems Sciences, JSPS Research fellow (DC2)
  • 2013/04/01, 2014/03/31, Hirhoshima University, Graduate School of Science,Department of Earth and Planetary Systems Sciences, JSPS Research fellow (PD)

Educational Backgrounds

  • Hiroshima University, Graduate School of Science , Japan, 2010/04, 2013/03
  • Hiroshima University, Graduate School of Science , Japan, 2008/04, 2010/03
  • Hiroshima University, School of Science, Japan, 2004/04, 2008/03

Academic Degrees

  • Hiroshima University
  • Hiroshima University

In Charge of Primary Major Programs

  • Earth and Planetary Systems Science

Research Fields

  • Mathematical and physical sciences;Earth and planetary science;Solid earth and planetary physics
  • Mathematical and physical sciences;Earth and planetary science;Geology
  • Mathematical and physical sciences;Earth and planetary science;Petrology / Mineralogy / Economic geology

Research Keywords

  • subduction zone, plate tectonics, earthquake, oceanic crust, mantle, metamorphic rocks, rheology, friction, permeability, serpentine

Affiliated Academic Societies

  • Japan Geoscience Union
  • Geological Society of Japan
  • American Geophysical Union

Educational Activity

Course in Charge

  1. 2026, Liberal Arts Education Program1, Intensive, Introduction to Science
  2. 2026, Liberal Arts Education Program1, Intensive, Introduction to Science
  3. 2026, Liberal Arts Education Program1, 2Term, Earth Science A
  4. 2026, Liberal Arts Education Program1, 1Term, Earth Science A
  5. 2026, Undergraduate Education, 2Term, Introduction to Earth and Planetary Sciences A
  6. 2026, Undergraduate Education, 2Term, Rock Deformation I
  7. 2026, Undergraduate Education, First Semester, Special Study for Graduation
  8. 2026, Undergraduate Education, Second Semester, Special Study for Graduation
  9. 2026, Undergraduate Education, 4Term, Petrology laboratory
  10. 2026, Undergraduate Education, 2Term, Experiments in General Geology A
  11. 2026, Graduate Education (Master's Program) , 3Term, Survey of Earth and Planetary Systems Science
  12. 2026, Graduate Education (Master's Program) , First Semester, Exercise for Globalization I
  13. 2026, Graduate Education (Master's Program) , Second Semester, Exercise for Globalization II
  14. 2026, Graduate Education (Master's Program) , Year, Externship for Earth and Planetary Systems Science
  15. 2026, Graduate Education (Master's Program) , Year, Integrated Seminar on Earth and Planetary Systems Science
  16. 2026, Graduate Education (Master's Program) , First Semester, Midterm Exercise for Earth and Planetary Systems Science
  17. 2026, Graduate Education (Master's Program) , First Semester, Special Exercise for Earth and Planetary Systems Science A
  18. 2026, Graduate Education (Master's Program) , Second Semester, Special Exercise for Earth and Planetary Systems Science B
  19. 2026, Graduate Education (Master's Program) , Year, Special Study for Earth and Planetary Systems Science
  20. 2026, Graduate Education (Doctoral Program) , Year, Special Study for Earth and Planetary Systems Science

Research Activities

Academic Papers

  1. Effects of Water on the Deformation of Rocks at the Brittle-Plastic Transition: Insight from High-pressure and High-temperature Deformation Experiment on Quartz, JOURNAL OF GEOGRAPHY-CHIGAKU ZASSHI, 135(1), 33-46, 2026
    Link to Paper Search Results by DOI
  2. Paleo-permeability in oceanic lithosphere inferred from vein mapping along the Wadi Haymiliyah of the Oman Ophiolite, PROGRESS IN EARTH AND PLANETARY SCIENCE, 13(1), 20260123
    Link to Paper Search Results by DOI
  3. Temperature and pressure dependence on slip systems in MgO: Insights from large-strain deformation experiments using the rotational diamond anvil cell☆, PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 369, 202512
    Link to Paper Search Results by DOI
  4. Crystallographic preferred orientation of (Mg,Fe)O up to 125 GPa inferred from torsional deformation experiments using a rotational diamond anvil cell, PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 369, 202506
    Link to Paper Search Results by DOI
  5. Carbonation and deformation of oceanic serpentinites in the Elba subduction channel: Evidence for fluid-rock interaction at seismogenic depth, EARTH AND PLANETARY SCIENCE LETTERS, 666, 20250915
    Link to Paper Search Results by DOI
  6. Plate Interface Shear Zone in the Sanbagawa Metamorphic Belt, Constrained by RSCM Thermometry, U-Pb Zircon Dating and Phase Equilibria Modelling in the Sarutagawa Region, Central Shikoku, Japan, JOURNAL OF METAMORPHIC GEOLOGY, 43(3), 257-285, 202504
    Link to Paper Search Results by DOI
  7. Fault-fracture mesh development produces tectonic tremor in fluid-overpressured serpentinized mantle wedge, COMMUNICATIONS EARTH & ENVIRONMENT, 6(1), 20250305
    Link to Paper Search Results by DOI
  8. Effect of particle characteristics on granular friction evaluated by dual-slip-plane friction tests, PROGRESS IN EARTH AND PLANETARY SCIENCE, 12(1), 20250312
    Link to Paper Search Results by DOI
  9. Near-infrared focused heating method for the rotational diamond anvil cell, REVIEW OF SCIENTIFIC INSTRUMENTS, 95(7), 20240701
    Link to Paper Search Results by DOI
  10. A history of mild shocks experienced by the regolith particles on hydrated asteroid Ryugu, NATURE ASTRONOMY, 7(6), 669-677, 202306
    Link to Paper Search Results by DOI
  11. Role of mantle carbonation in trench outer-rise region in the global carbon cycle, ISLAND ARC, 32(1), 202309
    Link to Paper Search Results by DOI
  12. Paleo-Permeability Structure of the Crustal Section of the Samail Ophiolite Based on Automated Detection of Veins in X-Ray CT Core Images From the Oman Drilling Project, GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, 24(6), 202306
    Link to Paper Search Results by DOI
  13. Cross-Property Relationship Between Electrical Resistivity and Elastic Wave Velocity of Crustal Rocks From the Oman Drilling Project Hole GT3A: Implications for in Situ Geophysical Properties of Oceanic Crust, JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 128(6), 202306
    Link to Paper Search Results by DOI
  14. Development of Lattice-Preferred Orientations of MgO Periclase From Strain Rate Controlled Shear Deformation Experiments Under Pressure up to 120 GPa, GEOPHYSICAL RESEARCH LETTERS, 49(21), 20221116
    Link to Paper Search Results by DOI
  15. Deformation and Material Transfer in a Fossil Subduction Channel: Evidence From the Island of Elba (Italy), TECTONICS, 41(7), 202207
    Link to Paper Search Results by DOI
  16. The evolution of rock friction is more sensitive to slip than elapsed time, even at near-zero slip rates, Proceedings of the National Academy of Sciences, 119(30), e2119462119, 20220620
  17. Simultaneous Measurements of Elastic Wave Velocity and Porosity of Epidosites Collected From the Oman Ophiolite: Implication for Low V-P/V-S Anomaly in the Oceanic Crust, GEOPHYSICAL RESEARCH LETTERS, 49(11), 20220616
    Link to Paper Search Results by DOI
  18. ★, Major Mineral Fraction and Physical Properties of Carbonated Peridotite (Listvenite) From ICDP Oman Drilling Project Hole BT1B Inferred From X-Ray CT Core Images, Journal of Geophysical Research: Solid Earth, 126, e2021JB022719, 20211029
  19. ★, Rheology of the fluid oversaturated fault zones at the brittle-plastic transition, Journal of Geophysical Research: Solid Earth, 126, e2020JB020804, 20201226
  20. Deformation of mafic schists from subducted oceanic crust at high pressure and temperature conditions, Tectonphysics, 774, 20191109
  21. ★, Dehydration of lawsonite can directly trigger earthquakes in subducting oceanic crust, Nature, 530, 81-84, 20160204
  22. ★, Slow stick–slip of antigorite serpentinite under hydrothermal conditions as a possible mechanism of slow earthquakes, Geophysical Research Letter, 42, 1099-1104, 20150130
  23. Permeability, porosity and pore geometry evolution during compaction of Neogene sedimentary rocks, Journal of Structural Geology, 62, 1-12, 20140111
  24. Shear-induced permeability anisotropy of simulated serpentinite gouge produced by triaxial deformation experiments, Geophysical Research Letter, 40, 1-5, 20130226