Spatio-temporal change of the seismicity in off-Tohoku region based on the analysis of dynamic seafloor pressure change

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K14818
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: National Research Institute for Earth Science and Disaster Prevention
• Principal Investigator: Kubota Tatsuya 国立研究開発法人防災科学技術研究所, 地震津波火山ネットワークセンター, 特別研究員 (70808071)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 津波 / 地震 / 海底圧力計

Outline of Final Research Achievements

This project studies offshore seismicity in detail by utilizing the high-frequency seismic component of ocean-bottom pressure gauges, which has not been utilized so far, and investigated the characteristics of the seismogenesis in the subduction zone that can cause huge earthquakes. Based on the theory of tsunami generation, we proposed a method to separate the seismic wave component from the complex ocean-bottom pressure records installed just above the epicenter, including the seismic and tsunami components. This study also estimated fault models for offshore earthquakes with high resolution based on pressure records to discuss the fault properties such as stress conditions.

Free Research Field

固体地球物理学

Academic Significance and Societal Importance of the Research Achievements

沖合の震源域直上の海底圧力計データが記録したシグナルを丹念に解析することで，沖合で発生した地震の震源の情報を非常に詳細に得ることができ，地震発生を特徴づける場の状態を詳細に知ることができることがわかった．近年では沖合に広域な海底ケーブル式海底圧力観測網が展開されてきている．秒から年まで幅広い時間スケールの地球物理学現象を観測可能である海底圧力計は次世代の観測の一端を担いうることを示したと言える．