Seismic activity and deformation process of the overriding plate in the northeastern Japan subduction zone

Akira Hasegawa, Akira Yamamoto, Norihito Umino, Satoshi Miura, Shigeki Horiuchi, Dapeng Zhao, Hiroki Sato

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

We estimated the temperature distribution within the crust of the northeastern Japan arc from P wave velocity perturbations obtained by travel time tomography. By comparing the estimated temperature distribution with the focal depth distribution of shallow, precisely relocated microearthquakes, we found that the brittle to ductile or stick-slip to stable-sliding transition occurs at the ~400°C isotherm and that the transition depth has considerable lateral variations. The brittle seismogenic zone, the upper portion of the crust, becomes locally thin in the P wave low-velocity areas, where the temperature is estimated to be relatively high. Concentration of shallow microearthquakes, high topography and relatively large contractile deformation of the crust are also observed in these low-velocity areas. Active faults are not distributed in the low-velocity areas but lie just along the edge of those areas or outside them. All these observations suggest that earthquake occurrence and deformation within the crust is governed, to a considerable degree, by the thermal regime of this volcanic arc, which is characterized by a horizontally inhomogeneous distribution of temperature. (C) 2000 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Pages (from-to)225-239
Number of pages15
JournalTectonophysics
Volume319
Issue number4
DOIs
Publication statusPublished - 2000 Apr 20

Keywords

  • Northeastern Japan arc
  • Seismic velocity perturbations
  • Temperature distribution
  • Travel time tomography

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

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