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

• 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
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 津波 / 地震 / 海底圧力計 / 海底動圧変動 / 2011年東北地方太平洋沖地震

Outline of Research at the Start

沈み込み帯における地震活動の詳細な把握は，2011年東北沖地震のような巨大地震の発生や関連現象の理解には必要不可欠である．今後，東北沖地震の直前・直後の観測記録が増えることはないため，東北沖地震前後の地震活動を詳細に明らかにするにはこれまでに得られた観測記録をさらに活用する必要がある．本研究はこれまで着目されてこなかった海底圧力計の地震動成分（動圧成分）に着目し，東北沖の地震発生場の時間的・空間的な変化（例：2011年東北沖地震前後の応力場の変化）の解明を試みる．

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.

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．

Research Products

• [Journal Article] A new mechanical perspective on a shallow megathrust near-trench slip from the high-resolution fault model of the 2011 Tohoku-Oki earthquake (2022)
  • Author(s): Kubota, T., Saito, T., & Hino, R.
  • Journal Title: Progress in Earth and Planetary Science Volume: 9 Issue: 1 Pages: 68-68
  • DOI: 10.1186/s40645-022-00524-0
  • Peer Reviewed / Open Access
• [Journal Article] Global fast-traveling tsunamis driven by atmospheric Lamb waves on the 2022 Tonga eruption (2022)
  • Author(s): Kubota, T., Saito, T., & Nishida, K.
  • Journal Title: Science Volume: 377 Issue: 6601 Pages: 91-94
  • DOI: 10.1126/science.abo4364
  • Peer Reviewed
• [Journal Article] Earthquake Rupture and Tsunami Generation of the 2015 Mw 5.9 Bonin Event Revealed by In Situ Pressure Gauge Array Observations and Integrated Seismic and Tsunami Wave Simulation (2021)
  • Author(s): Kubota Tatsuya、Saito Tatsuhiko、Fukao Yoshio、Sugioka Hiroko、Ito Aki、Tonegawa Takashi、Shiobara Hajime、Yamashita Mikiya
  • Journal Title: Geophysical Research Letters Volume: 48 Issue: 22
  • DOI: 10.1029/2021gl095915
  • Peer Reviewed / Open Access
• [Journal Article] Meteotsunami Observed by the Deep‐Ocean Seafloor Pressure Gauge Network Off Northeastern Japan (2021)
  • Author(s): Kubota Tatsuya、Saito Tatsuhiko、Chikasada Naotaka Y.、Sandanbata Osamu
  • Journal Title: Geophysical Research Letters Volume: 48 Issue: 21
  • DOI: 10.1029/2021gl094255
  • Peer Reviewed / Open Access
• [Journal Article] Improving the Constraint on the Mw 7.1 2016 Off‐Fukushima Shallow Normal‐Faulting Earthquake With the High Azimuthal Coverage Tsunami Data From the S‐Net Wide and Dense Network: Implication for the Stress Regime in the Tohoku Overriding Plate (2021)
  • Author(s): Kubota Tatsuya, Kubo Hisahiko, Yoshida Keisuke, Chikasada Naotaka Y., Suzuki Wataru, Nakamura Takeshi, Tsushima Hiroaki
  • Journal Title: Journal of Geophysical Research: Solid Earth Volume: 126 Issue: 10
  • DOI: 10.1029/2021jb022223
  • Peer Reviewed / Open Access
• [Journal Article] Detection of “Rapid” Aseismic Slip at the Izu‐Bonin Trench (2021)
  • Author(s): Fukao Yoshio、Kubota Tatsuya、Sugioka Hiroko、Ito Aki、Tonegawa Takashi、Shiobara Hajime、Yamashita Mikiya、Saito Tatsuhiko
  • Journal Title: Journal of Geophysical Research: Solid Earth Volume: 126 Issue: 9
  • DOI: 10.1029/2021jb022132
  • Peer Reviewed / Open Access
• [Journal Article] Impulsive Tsunami and Large Runup Along the Sanriku Coast of Japan Produced by an Inelastic Wedge Deformation Model (2021)
  • Author(s): Du Yue、Ma Shuo、Kubota Tatsuya、Saito Tatsuhiko
  • Journal Title: Journal of Geophysical Research: Solid Earth Volume: 126 Issue: 8
  • DOI: 10.1029/2021jb022098
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Meteorological tsunami generation due to sea-surface pressure change: Three-dimensional theory and synthetics of ocean-bottom pressure change (2021)
  • Author(s): Saito, T., Kubota, T., Chikasada N. Y, Tanaka, Y., & Sandanbata, O.
  • Journal Title: Journal of Geophysical Research: Oceans Volume: 126 Issue: 5
  • DOI: 10.1029/2020jc017011
  • Peer Reviewed / Open Access
• [Journal Article] Extracting near-field seismograms from ocean-bottom pressure gauge inside the focal area: application to the 2011 Mw 9.1 Tohoku-Oki earthquake (2021)
  • Author(s): Kubota, T., Saito, T., Tsushima, H., Hino, R., Ohta, Y., Suzuki S, & Inazu D.
  • Journal Title: Geophysical Research Letters Volume: 48 Issue: 7
  • DOI: 10.1029/2020gl091664
  • Peer Reviewed / Open Access
• [Journal Article] Ultra-broadband seismic and tsunami wave observation of high-sampling ocean-bottom pressure gauge covering periods from seconds to hours (2020)
  • Author(s): Kubota, T., Saito, T., Chikasada, N. Y., & Suzuki, W.
  • Journal Title: Earth and Space Science Volume: 7 Issue: 10
  • DOI: 10.1029/2020ea001197
  • Peer Reviewed / Open Access
• [Journal Article] Millimeter‐Scale Tsunami Detected by a Wide and Dense Observation Array in the Deep Ocean: Fault Modeling of an Mw 6.0 Interplate Earthquake off Sanriku, NE Japan (2020)
  • Author(s): Kubota, T., T. Saito, W. Suzuki
  • Journal Title: Geophysical Research Letters Volume: 47 Issue: 4
  • DOI: 10.1029/2019gl085842
  • Peer Reviewed
• [Journal Article] Tsunami Modeling for the Deep Sea and Inside Focal Areas (2019)
  • Author(s): Saito, T., T. Kubota
  • Journal Title: Annual Review of Earth and Planetary Sciences Volume: 48 Issue: 1 Pages: 121-145
  • DOI: 10.1146/annurev-earth-071719-054845
  • Peer Reviewed
• [Journal Article] Fault model of the 2012 doublet earthquake, near the up-dip end of the 2011 Tohoku-Oki earthquake, based on a near-field tsunami: implications for intraplate stress state (2019)
  • Author(s): Kubota, T., R. Hino, D. Inazu, S. Suzuki
  • Journal Title: Progress in Earth and Planetary Science Volume: 6 Issue: 1 Pages: 67-67
  • DOI: 10.1186/s40645-019-0313-y
  • Peer Reviewed / Open Access
• [Journal Article] Migrations and Clusters of Shallow Very Low Frequency Earthquakes in the Regions Surrounding Shear Stress Accumulation Peaks Along the Nankai Trough (2019)
  • Author(s): Takemura, S. A. Noda, T. Kubota, Y. Asano, T. Matsuzawa, K. Shiomi
  • Journal Title: Geophysical Research Letters Volume: 46 Issue: 21 Pages: 11830-11840
  • DOI: 10.1029/2019gl084666
  • Peer Reviewed / Open Access
• [Presentation] Global tsunami propagation driven by atmospheric waves on the 2022 Hunga-Tonga eruption. (2022)
  • Author(s): Kubota, T., Saito, T., & Nishida, K.
  • Organizer: AGU Fall Meeting 2022
  • Int'l Joint Research / Invited
• [Presentation] 2022年1月15日のトンガの火山噴火に伴う全球規模の津波発生と伝播 (2022)
  • Author(s): 久保田達矢・齊藤竜彦・西田究
  • Organizer: 海洋調査技術学会第34回研究成果発表会
  • Invited
• [Presentation] 直上津波・測地観測に基づく2011年東北地震の浅部大すべりモデリング：浅部不均質構造による応力変化への影響 (2022)
  • Author(s): 久保田達矢・齊藤竜彦・日野亮太
  • Organizer: 日本地震学会2022年度秋季大会
• [Presentation] Fast-traveling tsunamis by atmospheric pressure disturbances on the 2022 Tonga eruption (2022)
  • Author(s): Saito, T., Kubota, T., & Nishida, K.
  • Organizer: AOGS 2022
  • Int'l Joint Research / Invited
• [Presentation] グローバル海底水圧観測網がとらえた2022年トンガ噴火による気圧波が励起した津波 (2022)
  • Author(s): 久保田達矢・齊藤竜彦・西田究
  • Organizer: 日本地球惑星科学連合2022年大会
  • Invited
• [Presentation] Extracting near-field in-situ ground motion waveforms with large displacements of the 2011 Tohoku-Oki earthquake from ocean bottom pressure change inside the focal area (2021)
  • Author(s): Kubota, T., Saito, T., Tsushima, H., Hino, R., Ohta, Y., Suzuki, S., & Inazu, D.
  • Organizer: AGU 2021 Fall Meeting
  • Int'l Joint Research
• [Presentation] Slip distribution of the 2003 Tokachi-Oki earthquake estimated using ocean-bottom pressure gauges inside the focal area (2021)
  • Author(s): Kim, S.B., Saito, T., Kubota, T., & Chang, S.-J.
  • Organizer: AGU 2021 Fall Meeting
  • Int'l Joint Research
• [Presentation] 東北沖地震のすべり分布と応力降下分布：海溝大すべりの原因の力学的考察 (2021)
  • Author(s): 久保田達矢・齊藤竜彦
  • Organizer: 日本地震学会2021年度秋季大会
• [Presentation] 地震滑りとスロースリップとを繋ぐ遷移領域滑りの検出 (2021)
  • Author(s): 深尾良夫・久保田達矢・杉岡裕子・伊藤亜妃・利根川貴志・塩原肇・山下幹也・齊藤竜彦
  • Organizer: 日本地震学会2021年度秋季大会
• [Presentation] 震源域直上の海底水圧計記録に基づく2011年東北地震の地震波放射過程に関する考察 (2021)
  • Author(s): 久保久彦・久保田達矢・齊藤竜彦
  • Organizer: 日本地震学会2021年度秋季大会
• [Presentation] Improving the constraint of the 2016 Off-Fukushima shallow normal-faulting earthquake with the high-coverage tsunami data from the S-net wide network: implication on the crustal stress in the overriding plate (2021)
  • Author(s): Kubota, T., Kubo, H., Chikasada, N. Y., Yoshida, K., Suzuki, W. & Nakamura, T.
  • Organizer: JpGU Meeting 2021
  • Int'l Joint Research
• [Presentation] 海底動的圧力変動成分記録から抽出した2011年東北沖地震の震源域内部の大振幅地震動波形 (2021)
  • Author(s): 久保田達矢・齊藤竜彦・対馬弘晃・日野亮太・太田雄策・鈴木秀市・稲津大祐
  • Organizer: 日本地球惑星科学連合2021年大会
• [Presentation] 陸海観測データに基づく2016年福島県沖地震の震源過程解析 (2021)
  • Author(s): 久保久彦・久保田達矢・鈴木亘・中村武史
  • Organizer: 日本地球惑星科学連合2021年大会
  • Invited
• [Presentation] Rupture and tsunami generation process of the 2015 Mw 5.9 Bonin earthquake revealed by in-situ pressure gauge array observations and an integrated simulation of seismic and tsunami waves (2020)
  • Author(s): Kubota, T., Saito, T., Fukao, Y., Sugioka, H., Ito, A., Tonegawa, T., Shiobara, H., & Yamashita, M.
  • Organizer: AGU 2020 Fall Meeting
  • Int'l Joint Research
• [Presentation] Detection of "rapid" aseismic slip that bridges a gap between seismic slip and slow slip (2020)
  • Author(s): Fukao, Y., Kubota, T., Sugioka, H., Ito, A., Tonegawa, T., Yamashita, M., Shiobara, H., & Saito, T.
  • Organizer: AGU 2020 Fall Meeting
  • Int'l Joint Research
• [Presentation] The ability of the non-tidal oceanographic model for the ocean bottom pressure time series in the dense observation networks around Japan :toward understanding the transient crustal deformation (2020)
  • Author(s): Otsuka, H., Ohta, Y., Hino, R., Kubota, T., & Inazu, D.
  • Organizer: AGU 2020 Fall Meeting
  • Int'l Joint Research
• [Presentation] S-net沖合海底圧力観測網が記録した2020年7月1日に発生した気象津波 (2020)
  • Author(s): 久保田達矢・齊藤竜彦・近貞直孝・三反畑修
  • Organizer: 日本地震学会2020年度秋季大会
• [Presentation] 海面の気圧変化による津波の発生: 沖合水圧観測のための3次元モデル (2020)
  • Author(s): 齊藤竜彦・久保田達矢・近貞直孝・田中裕介・三反畑修
  • Organizer: 日本地震学会2020年度秋季大会
• [Presentation] DONET海底水圧計記録に対する非潮汐海洋モデルの適用とその評価 (2020)
  • Author(s): 大塚英人・太田雄策・日野亮太・久保田達矢・稲津大祐
  • Organizer: 日本地震学会2020年度秋季大会
• [Presentation] Millimeter-scale tsunami of an M6 earthquake observed by the nearest-field pressure gauge array: a fault modeling and stress drop estimation (2020)
  • Author(s): Kubota, T., Saito, T., & Suzuki, W.
  • Organizer: JpGU-AGU Joint Meeting 2020
  • Int'l Joint Research / Invited
• [Presentation] Tsunami analysis using the S-net pressure gauge records during the Mw 7.0 Off-Fukushima earthquake on 22 November 2016 to reduce the effects of tsunami-irrelevant pressure components (2020)
  • Author(s): Kubota, T., Chikasada, N. Y., Tsushima, H., Suzuki, W., Nakamura, T., & Kubo, H.
  • Organizer: JpGU-AGU Joint Meeting 2020
  • Int'l Joint Research
• [Presentation] 地殻変動検出に向けた日本海溝北部におけるS-net長期間水圧記録の品質の予備的検討 (2020)
  • Author(s): 久保田達矢・近貞直孝・日野亮太・太田雄策・大塚英人
  • Organizer: JpGU-AGU Joint Meeting 2020
• [Presentation] S-net水圧データ即時解析のための長期評価 (2020)
  • Author(s): 近貞直孝・久保田達矢
  • Organizer: JpGU-AGU Joint Meeting 2020
• [Presentation] Strain release by メrapidモ aseismic slip at the Izu-Bonin trench (2020)
  • Author(s): Fukao, Y., Sugioka, H., Ito, A., Tonegawa, T., Yamashita, M., Shiobara, H., Kubota, T., & Saito, T.
  • Organizer: JpGU-AGU Joint Meeting 2020
  • Int'l Joint Research
• [Presentation] 日本近海の海底圧力計データに対する非潮汐海洋成分の影響評価 (2020)
  • Author(s): 大塚英人・太田雄策・日野亮太・久保田達矢・稲津大祐
  • Organizer: JpGU-AGU Joint Meeting 2020
• [Presentation] 津波波源自動解析システムMarlinの開発 (2020)
  • Author(s): 鈴木亘・久保田達矢・中村武史・近貞直孝
  • Organizer: JpGU-AGU Joint Meeting 2020
• [Presentation] CMT inversion of offshore earthquakes along the Nankai Trough: Separated distributions of slow and regular earthquakes on the plate boundary (2020)
  • Author(s): Takemura, S., Okuwaki, R., Kubota, T., Shiomi K., Kimura, T., & Noda, A.
  • Organizer: JpGU-AGU Joint Meeting 2020
  • Int'l Joint Research
• [Presentation] Fault modeling and stress drop estimation based on millimeter-scale tsunami records of an M6 earthquake detected by the dense and wide pressure gauge array (2020)
  • Author(s): Kubota, T., Saito, T., & Suzuki, W.
  • Organizer: EGU General Assembly 2020
  • Int'l Joint Research
• [Presentation] Can inelastic wedge deformation explain the large tsunami runup of the 1896 Sanriku earthquake? (2020)
  • Author(s): Du, Y., Ma, S., Kubota, T., Saito, T.
  • Organizer: SSA 2020 Annual Meeting
  • Int'l Joint Research
• [Presentation] Ultra-broadband observations of seismic and tsunami waves of ocean bottom pressure gauges off the NE Japan and spectral analysis combined with the records of seismometers and tide gauges (2019)
  • Author(s): Kubota, T., T. Saito, N. Y. Chikasada, W. Suzuki
  • Organizer: AGU 2019 Fall Meeting
  • Int'l Joint Research
• [Presentation] 2015年Mw6.0小笠原海溝地震の近地アレー観測：津波発生場の海底水圧変動モデリング (2019)
  • Author(s): 久保田達矢・齊藤竜彦・深尾良夫・杉岡裕子・伊藤亜妃・山下幹也・利根川貴志・塩原肇
  • Organizer: 日本地震学会2019年度秋季大会
• [Presentation] 2015年Mw6.0小笠原海溝地震の近地アレー観測：前震―本震―海底変動―津波発生―余効変動 (2019)
  • Author(s): 深尾良夫・杉岡裕子・伊藤亜妃・山下幹也・利根川貴志・塩原肇・久保田達矢・齊藤竜彦
  • Organizer: 日本地震学会2019年度秋季大会
• [Presentation] 日本近海に設置された海底圧力計が捉えた2010年チリ地震に伴う地震レイリー波と津波の群速度分散 (2019)
  • Author(s): 久保田達矢・齊藤竜彦・近貞直孝・鈴木亘
  • Organizer: 日本地震学会2019年度秋季大会
• [Presentation] Spatiotemporal variations of shallow very low-frequency earthquake activities along the Nankai Trough (2019)
  • Author(s): Takemura, S., Y. Asano, T. Matsuzawa, A. Noda, T. Kubota, K. Shiomi
  • Organizer: 27th IUGG General Assembly
  • Int'l Joint Research
• [Presentation] 2012年宮城沖プレート内ダブレット地震の震源断層モデルから検討した日本海溝近傍における海洋プレート内レオロジー (2019)
  • Author(s): 久保田達矢・日野亮太・鈴木秀市
  • Organizer: 日本地球惑星科学連合2019年大会
• [Remarks] 震源域直上津波波形記録にもとづく断層モデル推定と2011年東北沖地震の浅部大すべりの力学的メカニズム
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2022_PEPS/
• [Remarks] 2022年トンガ噴火に伴う地球規模の津波発生と伝播メカニズム
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2022_Science/
• [Remarks] 2022年1月トンガ噴火に伴う地球規模の津波発生と伝播メカニズムを解明
  • URL: https://www.bosai.go.jp/info/press/2022/20220513.html
• [Remarks] 震源直上の稠密海底水圧アレイ観測が記録した津波発生場の海底水圧変動
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2021_GRL2/
• [Remarks] S-netが捉えた『気象津波』：大気圧変動が引き起こす津波
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2021_GRL1/
• [Remarks] S-net広域・稠密津波観測網が明らかにした東北沖の大陸プレート内部の応力状態
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2021_JGR/
• [Remarks] 海底水圧計が記録した2011年東北地震の震源直上の地震動
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2021_GRL/index.html
• [Remarks] 海底圧力計の超広帯域な地震・津波観測
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2020_ESS/index.html
• [Remarks] 防災科学技術研究所地震津波防災研究部門 久保田達矢 個人Webページ
  • URL: https://quaketm.bosai.go.jp/~kubota/index.html
• [Remarks] ミリメートル津波を用いた三陸沖M6地震の震源断層モデルの推定
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2020_GRL/index.html
• [Remarks] 2011年東北沖地震後の沈み込むプレートの応力場の変化
  • URL: https://quaketm.bosai.go.jp/~kubota/publications/Kubota_etal_2019_PEPS/index.html
• [Remarks] Kubota et al. (2020 Geophys Res Lett) 最終原稿
  • URL: https://quaketm.bosai.go.jp/~kubota/uploads/draft/Kubota_etal_2020_GRL.pdf
• [Remarks] Kubota et al. (2019 Prog Earth Planet Sci) 最終原稿
  • URL: https://quaketm.bosai.go.jp/~kubota/uploads/draft/Kubota_etal_2019_PEPS.pdf