Relocating the 2011 Tohoku-oki earthquakes (M 6.0-9.0)

Zhouchuan Huang, Dapeng Zhao

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The great Tohoku-oki earthquake (Mw 9.0) on 11 March 2011 was accompanied by nearly 100 large foreshocks and aftershocks (M. ≤. 6.0) in the Northeast Japan forearc. In this study we relocated 77 of these large events using three different velocity models. An updated three-dimensional velocity model significantly reduced the travel-time residuals in the earthquake relocation. We found that the large thrust earthquakes are generally located in or around high-velocity patches, suggesting that the generation of the large thrust earthquakes is controlled by structural heterogeneities in the megathrust zone. The high-velocity patches may represent asperities in the megathrust zone where the subducting Pacific plate and the overriding Okhotsk plate may be coupled strongly. Many non-thrust earthquakes occurred in the crust of the overriding Okhotsk plate, indicating that the stress field there has been changed by the Tohoku-oki mainshock. The present results may improve our understanding of the subduction dynamics and seismotectonics of the Northeast Japan arc.

Original languageEnglish
Pages (from-to)35-45
Number of pages11
JournalTectonophysics
Volume586
DOIs
Publication statusPublished - 2013 Feb 26

Keywords

  • Asperity
  • Earthquake location
  • Megathrust zone
  • Pacific slab
  • Stress field
  • Subduction zones

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

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