JP

Organization

Research Division

Endowed Research Division
Uehiro Disaster Risk Reduction Research Division
Assistant Professor
Ph. D.
Research Subject(s)
Various slip phenomena, including earthquakes and slow slips, occur on faults beneath the ground where we live. I aim to reveal physical mechanisms governing fault slip behavior through studies of crustal deformation due to these fault slips using satellite data, including GPS and SAR.
Key Words
Crustal Deformation / GPS / SAR / Slow Slip / Earthquake
Website
Research Activities

Detection of small slow slips
Slow slips are a fault slip phenomenon without radiating seismic waves and are attracting attention in relation to earthquakes. Generally, surface displacements due to slow slips are small (several millimeters). Thus, detecting slow slips using GPS data is often difficult. I developed a method for detecting small slow slips and estimating their characteristic parameters, and we applied it to southwest Japan, southcentral Alaska, and northeast Japan. We identified hundreds of slow slips and clarified the physical features of the regions where slow slips occur.

Selected Works

Y. Okada, T. Nishimura, T. Tabei, T. Matsushima, & H. Hirose (2022) Development of a detection method for short-term slow slip events using GNSS data and its application to the Nankai subduction zone. Earth, Planets and Space 74, 18. https://doi.org/10.1186/s40623-022-01576-8

Y. Okada & T. Nishimura (2023) Systematic detection of short-term slow slip events in southcentral Alaska. Geophysical Research Letters 50, e2023GL104901. https://doi.org/10.1029/2023GL104901

Y. Okada & T. Nishimura (2025) Investigation on short-term slow slip events in the northeast Japan subduction zones using decadal GNSS data. Earth, Planets and Space 77, 45. https://doi.org/10.1186/s40623-025-02175-z

T. Nishikawa, T. Nishimura, & Y. Okada (2021) Earthquake swarm detection along the Hikurangi Trench, New Zealand: Insights into the relationship between seismicity and slow slip events. Journal of Geophysical Research: Solid Earth, 126, e2020JB020618. https://doi.org/10.1029/2020JB020618

S. Takemura, Y. Hamada, H. Okuda, Y. Okada, K. Okubo, T. Akuhara, A. Noda, & T. Tonegawa (2023) A review of shallow slow earthquakes along the Nankai Trough. Earth Planets Space 75, 164. https://doi.org/10.1186/s40623-023-01920-6

Selected Memberships
  • The Geodetic Society of Japan
  • The Seismological Society of Japan
  • Japan Geoscience Union
  • American Geophysical Union
Selected Awards
  • DPRI Annual Meeting 2020 Excellent Presentation Award
  • JpGU meeting 2023 Outstanding Student Presentation Award
  • EPS Young Researcher Award 2024