Episodic tremor and slip near the Japan Trench prior to the 2011 Tohoku-Oki earthquake

Yoshihiro Ito, Ryota Hino, Syuichi Suzuki, Yoshiyuki Kaneda

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Change in the rates of aseismic deformation prior to large earthquakes is a major area of interest in earthquake physics. Here we present evidence that episodic tremor and slip occurred in the shallow subduction zone within the source region of the 2011 Tohoku-Oki earthquake prior to the main shock. Ocean bottom seismometers near the Japan Trench recorded some excitations in amplitude of ambient noise level accompanying both the 2008 and 2011 slow slip events. The observed signals show that low frequencies of 5-8Hz dominated, suggesting that the excitations were due to small low-frequency tremors accompanying the slow slip events. The largest amplitude tremor was observed just before the 2011 event. The estimated sources of tremors were possibly distributed within the coseismic slip area of the 2011 event, suggesting the shallow plate-boundary thrust near the trench is a general location of slow earthquakes. Key Points Tremor signal accompanied slow slip event Tremor activity accelerated before the 2011 Tohoku-Oki earthquake Possible tremor source located near the trench within coseismic slip area

Original languageEnglish
Pages (from-to)1725-1731
Number of pages7
JournalGeophysical Research Letters
Volume42
Issue number6
DOIs
Publication statusPublished - 2015 Mar 28

Keywords

  • 2011 Tohoku-Oki earthquake
  • episodic tremor and slip
  • ocean bottom seismometer
  • subduction zone

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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