東北地方太平洋沖地震の地震前・地震時・地震後の固着状態とすべり分布の推定

• Project Area: Crustal dynamics-Unified understanding of intraisland deformation after the great Tohoku-oki earthquake-
• Project/Area Number: 15H01140
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Kobe University
• Principal Investigator: 吉岡 祥一 神戸大学, 都市安全研究センター, 教授 (20222391)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000); Fiscal Year 2016: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2015: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
• Keywords: GEONET / 固着域 / プレスリップ / トレンド / チェビシェフ多項式 / 東北地方太平洋沖地震 / GPS / インヴァ―ジョン / 固着状態 / 地震

Outline of Annual Research Achievements

東北地方のGEONETの電子基準点で得られたデータを用いて、プレート運動によるテクトニックな水平・上下変動を求め、インヴァージョン解析によりプレート間の固着と非地震性すべりの時空間分布を推定した．解析期間は2011年東北地方太平洋沖地震(M9.0)直前の7年間とした．新潟県の３点のテクトニックな変動を平均し、参照点の変動とした．チェビシェフ多項式を用いてテクトニックな変動を高精度で求めることを可能にし、最適の多項式の次数はAICの値を最小にするように求めた．地震時とアンテナ交換に伴うステップを除去した後、顕著な余効変動がみられた2003年十勝沖地震（M8.0）、2005年宮城県沖地震(M7.2)、2008年岩手宮城内陸地震(M7.2)の余効変動を対数関数で近似し、その影響を取り除いた．さらに、解析に使用した全観測点の時系列データから求めた共通誤差成分と、年周・半年周成分を取り除き、テクトニックな変動を抽出した．解析期間を通して、岩手県、宮城県の太平洋側の観測点では2cm/年の西向きの水平変位が継続してみられ、上下変位は、太平洋側で沈降、日本海側で隆起していた．福島県の太平洋側では2008年～2011年に西向きの変動が小さくなっていた．テクトニックな地殻変動を基にインヴァージョン解析を行い、1年ごとにプレート間の固着とすべりの時空間分布を推定した．解析には、すべりの空間分布が滑らか、すべりは主にプレート収束方向を向く、すべりの時間変化滑らかという３つの先験的情報を与えたインヴァージョン法を用いた．その結果、2004年～2010年、宮城県沖で約10cm/年のプレート間の固着が得られ、三陸沖中部では2004年に約2cm/年だった固着が、徐々に小さくなり2010年にはほぼ見られなくなった．

Research Progress Status

28年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

28年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] テキサス大学(米国)
• [Journal Article] Slab dehydration and earthquake distribution beneath southwestern and central Japan based on three-dimensional thermal modeling (2017)
  • Author(s): Ji, Y., and S. Yoshioka
  • Journal Title: Geophysical Research Letters Volume: 44 Issue: 6 Pages: 2679-2686
  • DOI: 10.1002/2016gl072295
  • NAID: 120006489852
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Relationships among temperature, dehydration of the subducting Philippine Sea plate, and the occurrence of a megathrust earthquake, low-frequency earthquakes, and a slow slip event in the Tokai district, central Japan (2016)
  • Author(s): Suenaga, N., S. Yoshioka, and T. Matsumoto
  • Journal Title: Physics of the Earth and Planetary Interiors Volume: 260 Pages: 44-52
  • DOI: 10.1016/j.pepi.2016.09.004
  • Peer Reviewed / Open Access
• [Journal Article] Three-dimensional numerical modeling of thermal regime and slab dehydration beneath Kanto and Tohoku, Japan (2016)
  • Author(s): Ji, Y., S. Yoshioka, V. C. Manea, M. Manea, and T. Matsumoto
  • Journal Title: Journal of Geophysical Research Volume: 122 Issue: 1 Pages: 332-353
  • DOI: 10.1002/2016jb013230
  • NAID: 120006489853
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Spatiotemporal slip distributions of three long-term slow slip events beneath the Bungo Channel, southwest Japan, inferred from inversion analyses of GPS data (2015)
  • Author(s): Yoshioka, S., Matsuoka, Y. and S. Ide
  • Journal Title: Geophysical Journal International Volume: 201 Issue: 3 Pages: 1437-1466
  • DOI: 10.1093/gji/ggv022
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Relationship between temperatures and fault slips on the upper surface of the subducting Philippine Sea plate beneath the Kanto district, central Japan (2015)
  • Author(s): Yoshioka, S., R. Takagi and T. Matsumoto
  • Journal Title: Geophysical Journal International Volume: 201 Issue: 2 Pages: 878-890
  • DOI: 10.1093/gji/ggv032
  • Peer Reviewed
• [Presentation] Three-dimensional thermal modeling associated with subduction of the Cocos plate beneath southern Mexico, and its relationship to the occurrence of interplate seismic events (2016)
  • Author(s): Suenaga, N., Y. Ji, S. Yoshioka, M. Manea, and V. C. Manea
  • Organizer: AGU Chapman Conference on the Slow Slip Phenomena
  • Place of Presentation: Ixtapa(Mexico)
  • Year and Date: 2016-02-24
  • Int'l Joint Research
• [Presentation] Seismic distribution and dehydration of MORB associated with subduction of the Pacific and the Philippine Sea plates beneath the Tohoku and Kanto districts, Japan (2016)
  • Author(s): Ji, Y. and S. Yoshioka
  • Organizer: AGU Chapman Conference on the Slow Slip Phenomena
  • Place of Presentation: Ixtapa(Mexico)
  • Year and Date: 2016-02-24
  • Int'l Joint Research
• [Presentation] Three-dimensional thermal modeling associated with subduction of the Philippine Sea plate, southwest Japan,AGU Chapman Conference on the Slow Slip Phenomena (2016)
  • Author(s): Yoshioka, S., Y. Ji and T. Matsumoto
  • Organizer: AGU Chapman Conference on the Slow Slip Phenomena
  • Place of Presentation: Ixtapa(Mexico)
  • Year and Date: 2016-02-24
  • Int'l Joint Research
• [Presentation] A Study of low-frequency earthquake magnitudes in northern Vancouver Island (2016)
  • Author(s): Chuang, L. Y., M. G. Bostock and S. Yoshioka
  • Organizer: AGU Chapman Conference on the Slow Slip Phenomena
  • Place of Presentation: Ixtapa(Mexico)
  • Year and Date: 2016-02-22
  • Int'l Joint Research
• [Presentation] Mapping Crustal Structure Change in Tohoku With Time-Varying P-to-S Receiver Functions (2016)
  • Author(s): Robert W. Porritt and Shoichi Yoshioka
  • Organizer: Crustal Dynamics 2016
  • Place of Presentation: 高山市民文化会館(岐阜県高山市)
  • Int'l Joint Research
• [Presentation] Slab Dehydration, Interplate Hydrousity and Seismic Distribution in Modeling deformation, faulting, and mountain building in the island-arc crust of northeastern and central Japan considering heterogeneous thermal structure (2016)
  • Author(s): Yingfeng Ji and Shoichi Yoshioka
  • Organizer: Crustal Dynamics 2016
  • Place of Presentation: 高山市民文化会館(岐阜県高山市)
  • Int'l Joint Research
• [Presentation] Geo-fluids distribution in mantle inferred from the electrical conductivity and simulated thermal (2016)
  • Author(s): Maki Hata, Makoto Uyeshima, Shoichi Yoshioka, Nobuaki Suenaga and Takumi Matsumoto
  • Organizer: 23rd Electromagnetic Induction Workshop
  • Place of Presentation: ChiangMai, Thailand(The Empress Hotel Chiang Mai)
  • Int'l Joint Research
• [Presentation] Three-dimensional numerical modeling of temperature and dehydration fields associated with subduction of the Philippine Sea plate, southwest Japan (2016)
  • Author(s): Shoichi Yoshioka, Yingfeng Ji and Takumi Matsumoto
  • Organizer: 35rd General Assembly of the European Seismological Commission
  • Place of Presentation: Trieste, Italy
  • Int'l Joint Research
• [Presentation] 3D thermal convection modeling associated with subduction of the Cocos plate in southern Mexico - Effects of trench retreat on temperature and flow fields - (2016)
  • Author(s): Nobuaki Suenaga, Yingfeng Ji, Shoichi Yoshioka, Vlad C. Manea and Maria Manea
  • Organizer: Joint Workshop on Slow Earthquakes 2016
  • Place of Presentation: 東京大学地震研究所１号館(東京都文京区)
  • Int'l Joint Research
• [Presentation] Three-dimensional numerical modeling of temperature and dehydration associated with subduction of the Philippine Sea plate, southwest Japan (2016)
  • Author(s): Shoichi Yoshioka, Yingfeng Ji and Takumi Matsumoto
  • Organizer: The 1st Asia-Pacific Workshop on Lithosphere and Mantle Dynamics
  • Place of Presentation: Taipei,China
  • Int'l Joint Research / Invited
• [Presentation] Slab dehydration, thermal regime, the distribution of tectonic tremors and seismicity beneath Hikurangi (2016)
  • Author(s): Yingfeng Ji and Shoichi Yoshioka
  • Organizer: 日本地震学会秋季大会
  • Place of Presentation: 名古屋国際会議場(愛知県名古屋市)
• [Presentation] Manea Numerical simulations of temperature, dehydration, and flow fields associated with subduction of the cocos plate, and its relation to the occurrence of interplate seismic events in southern mexico (2016)
  • Author(s): Nobuaki Suenaga ,Yingfeng Ji ,Shoichi Yoshioka, Maria Manea and Vlad C
  • Organizer: Annual Meeting 2016
  • Place of Presentation: Puerto Vallarta，Mexico
  • Int'l Joint Research
• [Presentation] Thermal regime, slab dehydration and seismicity distribution beneath the Hikurangi subduction zone based on 3D simulation (2016)
  • Author(s): Yingfeng Ji and Shoichi Yoshioka
  • Organizer: AGU FALL MEETING 2016
  • Place of Presentation: San Francisco，U.S.A.
  • Int'l Joint Research
• [Presentation] Manea Numerical simulations of temperature, dehydration, and flow fields associated with subduction of the Cocos plate, and its relation to the occurrence of interplate seismic events in southern Mexico (2016)
  • Author(s): Nobuaki Suenaga, Yingfeng Ji ,Shoichi Yoshioka ,Maria Manea and Vlad C
  • Organizer: AGU FALL MEETING 2017
  • Place of Presentation: San Francisco，U.S.A.
  • Int'l Joint Research
• [Presentation] A Study of low-frequency earthquake magnitudes in northern Vancouver Island (2015)
  • Author(s): Chuang, L. Y., M. G. Bostock and S. Yoshioka
  • Organizer: AGU Fall Meeting 2015
  • Place of Presentation: San Francisco(America)
  • Year and Date: 2015-12-16
  • Int'l Joint Research
• [Presentation] Crustal structure in the Tohoku region before and after the Tohoku-Oki earthquake with P to S receiver functions (2015)
  • Author(s): Porritt, R. W. and S. Yoshioka
  • Organizer: AGU Fall Meeting 2015
  • Place of Presentation: San Francisco(America)
  • Year and Date: 2015-12-14
  • Int'l Joint Research
• [Presentation] Impact of olivine-spinel phase change kinetics on the deformation of the Mariana Slab (2015)
  • Author(s): Riedel, M. R. and S. Yoshioka
  • Organizer: GeoBerlin 2015
  • Place of Presentation: Berlin(Germany)
  • Year and Date: 2015-10-06
  • Int'l Joint Research
• [Presentation] 東北地方太平洋沖地震の地震前・地震時・地震後の固着状態とすべり分布の推定 (2015)
  • Author(s): 吉岡祥一
  • Organizer: 地殻ダイナミクス －東北沖地震後の内陸変動の統一的理解－2015年研究集会
  • Place of Presentation: エポカ21（宮城県・栗原市）
  • Year and Date: 2015-09-27
• [Presentation] Temperatures and fault slips on the upper surface of the subducting Philippine Sea plate beneath the Kanto district, central Japan (2015)
  • Author(s): Yoshioka, S., R. Takagi and T. Matsumoto
  • Organizer: IUGG XXVI 2015
  • Place of Presentation: Prague(Czechia)
  • Year and Date: 2015-06-30
• [Presentation] 3-D thermal modeling associated with subduction of the Philippine Sea plate in southwest Japan. (2015)
  • Author(s): Yoshioka, S., Y. Ji and T. Matsumoto
  • Organizer: Central Asian tectonics and Western Pacific Geodynamics international workshop
  • Place of Presentation: Wuhan(China)
  • Year and Date: 2015-06-06
• [Presentation] 2D and 3D thermal modeling associated with subduction of the Philippine Sea plate in central and southwest Japan (2015)
  • Author(s): Yoshioka, S., Y. Ji and T. Matsumoto
  • Organizer: 東京大学地震研究所共同利用研究集会 沈み込み帯
  • Place of Presentation: 東京大学地震研究所（東京・文京区）
  • Year and Date: 2015-05-30
• [Remarks] 吉岡祥一ホームページ
  • URL: http://www2.kobe-u.ac.jp/~syoshiok/