日本列島下のスラブの三次元構造と地震活動  [in Japanese] Slab Structure beneath the Japanese Islands and Earthquake Generation  [in Japanese]

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Author(s)

    • 長谷川 昭 HASEGAWA Akira
    • 東北大学大学院理学研究科地震・噴火予知研究観測センター RCPEV, Graduate School of Science, Tohoku University
    • 中島 淳一 NAKAJIMA Junichi
    • 東北大学大学院理学研究科地震・噴火予知研究観測センター RCPEV, Graduate School of Science, Tohoku University
    • 弘瀬 冬樹 HIROSE Fuyuki
    • 気象研究所地震火山研究部 Seismology and Volcanology Research Department, Meteorological Research Institute
    • 北 佐枝子 KITA Saeko
    • 東北大学大学院理学研究科地震・噴火予知研究観測センター RCPEV, Graduate School of Science, Tohoku University
    • 松澤 暢 MATSUZAWA Toru
    • 東北大学大学院理学研究科地震・噴火予知研究観測センター RCPEV, Graduate School of Science, Tohoku University

Abstract

 A dense nationwide seismic network recently constructed in Japan has been yielding large volumes of high-quality data that have made it possible to investigate the seismic structure in the Japanese subduction zone with unprecedented resolution. We introduce a precise configuration of the Philippine Sea and Pacific plates subducting beneath the Japanese Islands, which was recently obtained by seismic tomographic imaging, precise earthquake hypocenter determinations, and focal mechanism studies. Seismic tomographic studies show that the Philippine Sea plate subducting beneath southwest Japan is continuous throughout the entire region, from Kanto to Kyushu, without disruption or splitting even beneath the area north of the Izu Peninsula. The estimated geometry of the subducted Pacific and Philippine Sea slabs shows a broad contact zone between the two slabs located directly beneath the Kanto plain. It further shows the wavy configuration of the Philippine Sea slab subducting beneath the entire region of southwestern Japan. Contact between the Philippine Sea plate and the Pacific plate causes anomalously deep interplate and intraslab earthquake activity in Kanto. Moreover, the interplate coupling coefficient estimated from repeating earthquake data shows a distinct change across the northeastern edge of this slab contact zone, suggesting that the overlying plate controls large-scale interplate coupling. High-resolution studies of spatial variations of intraslab seismicity and the seismic velocity structure of the slab crust strongly support the dehydration embrittlement hypothesis for the generation of intraslab earthquakes.

Journal

  • Journal of Geography (Chigaku Zasshi)

    Journal of Geography (Chigaku Zasshi) 119(2), 190-204, 2010-04-25

    Tokyo Geographical Society

References:  44

Cited by:  8

Codes

  • NII Article ID (NAID)
    10030368374
  • NII NACSIS-CAT ID (NCID)
    AN00322536
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0022135X
  • NDL Article ID
    10704577
  • NDL Source Classification
    ZM41(科学技術--地球科学)
  • NDL Call No.
    Z15-169
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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