P and S wave attenuation tomography of the Japan subduction zone

Zewei Wang, Dapeng Zhao, Xin Liu, Chuanxu Chen, Xibing Li

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

We determine the first high-resolution P and S wave attenuation (Q) tomography beneath the entire Japan Islands using a large number of high-quality t* data collected from P and S wave velocity spectra of 4222 local shallow and intermediate-depth earthquakes. The suboceanic earthquakes used in this study are relocated precisely using sP depth phases. Significant landward dipping high-Q zones are revealed clearly, which reflect the subducting Pacific slab beneath Hokkaido and Tohoku, and the subducting Philippine Sea (PHS) slab beneath SW Japan. Prominent low-Q zones are visible in the crust and mantle wedge beneath the active arc volcanoes in Hokkaido, Tohoku, and Kyushu, which reflect source zones of arc magmatism caused by fluids from the slab dehydration and corner flow in the mantle wedge. Our results also show that nonvolcanic low-frequency earthquakes (LFEs) in SW Japan mainly occur in the transition zone between a narrow low-Q belt and its adjacent high-Q zones right above the flat segment of the PHS slab. This feature suggests that the nonvolcanic LFEs are caused by not only fluid-affected slab interface but also specific conditions such as high pore pressure which is influenced by the overriding plate.

Original languageEnglish
Pages (from-to)1688-1710
Number of pages23
JournalGeochemistry, Geophysics, Geosystems
Volume18
Issue number4
DOIs
Publication statusPublished - 2017 Apr 1

Keywords

  • Japan subduction zone
  • seismic attenuation
  • tomography

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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