Hypocenter migration and crustal seismic velocity distribution observed for the inland earthquake swarms induced by the 2011 Tohoku-Oki earthquake in NE Japan: Implications for crustal fluid distribution and crustal permeability

Tomomi Okada, Toru Matsuzawa, Norihito Umino, Keisuke Yoshida, Akira Hasegawa, Hiroaki Takahashi, Takuji Yamada, Masahiro Kosuga, Tetsuya Takeda, Aitaro Kato, Toshihiro Igarashi, Kazushige Obara, Shinichi Sakai, Atsushi Saiga, Takashi Iidaka, Takaya Iwasaki, Naoshi Hirata, Noriko Tsumura, Yoshiko Yamanaka, Toshiko TerakawaHaruhisa Nakamichi, Takashi Okuda, Shinichiro Horikawa, Hiroshi Katao, Tsutomu Miura, Atsuki Kubo, Takeshi Matsushima, Kazuhiko Goto, Hiroki Miyamachi

Research output: Chapter in Book/Report/Conference proceedingChapter

4 Citations (Scopus)

Abstract

After the occurrence of the 2011 magnitude 9 Tohoku earthquake, seismicity in the overriding plate changed. This chapter considers some possible evidence of the influence of crustal fluid/water on the occurrence of the triggered seismicity after the 2011 Tohoku-Oki earthquake. It estimates the permeability from the observed hypocenter diffusion. Shallow seismic activity and crustal deformation are strongly affected by the water dehydrated and upwelling from the subducting Pacific plate. Spatiotemporal expansion of hypocenter areas of some earthquake swarms can be attributed to fluid diffusion. In the upper crust, the earthquakes seem to be distributed in seismic high-velocity areas rather than in seismic low-velocity areas. In the lower crust, the seismic low-velocity areas appear to be elongated along N-S or NE-SW, the strike of the island arc. The chapter also estimates three-dimensional seismic velocity structure using the double-difference tomography method.

Original languageEnglish
Title of host publicationCrustal Permeability
Publisherwiley
Pages307-323
Number of pages17
ISBN (Electronic)9781119166573
ISBN (Print)9781119166566
DOIs
Publication statusPublished - 2016 Oct 31

Keywords

  • Crustal deformation
  • Crustal seismic velocity distribution
  • Double-difference tomography method
  • Earthquake swarms
  • Fluid diffusion
  • Hypocenter migration
  • Pacific plate
  • Shallow seismic activity
  • Tohoku earthquake

ASJC Scopus subject areas

  • Engineering(all)
  • Environmental Science(all)

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