Slab Structure beneath the Japanese Islands and Earthquake Generation

• HASEGAWA Akira

  RCPEV, Graduate School of Science, Tohoku University

• NAKAJIMA Junichi

  RCPEV, Graduate School of Science, Tohoku University

• UCHIDA Naoki

  RCPEV, Graduate School of Science, Tohoku University

• HIROSE Fuyuki

  Seismology and Volcanology Research Department, Meteorological Research Institute

• KITA Saeko

  RCPEV, Graduate School of Science, Tohoku University

• MATSUZAWA Toru

  RCPEV, Graduate School of Science, Tohoku University

Bibliographic Information

Other Title

• 日本列島下のスラブの三次元構造と地震活動
• ニホン レットウ カ ノ スラブ ノ 3ジゲン コウゾウ ト ジシン カツドウ

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

  Tokyo Geographical Society

Keywords

• subduction zone
• slab structure
• earthquake generation
• interplate coupling
• dehydration embrittlement
• Japanese Islands

Details

• CRID: 1390282679207169152
• NII Article ID: 10030368374
• NII Book ID: AN00322536
• DOI: 10.5026/jgeography.119.190
• ISSN: 18840884
• ISSN: 0022135X
• NDL BIB ID: 10704577
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I10704577
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed