Dissecting large earthquakes in Japan: Role of arc magma and fluids

Dapeng Zhao, M. Santosh, Akira Yamada

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


We synthesized information from recent high-resolution tomographic studies of large crustal earthquakes which occurred in the Japanese Islands during 1995-2008. Prominent anomalies of low-velocity and high Poisson's ratio are revealed in the crust and uppermost mantle beneath the mainshock hypocenters, which may reflect arc magma and fluids that are produced by a combination of subducting slab dehydration and corner flow in the mantle wedge. Distribution of 164 crustal earthquakes (M 5.7-8.0) that occurred in Japan during 1885-2008 also shows a correlation with the distribution of low-velocity zones in the crust and uppermost mantle. A qualitative model is proposed to explain the geophysical observations recorded so far in Japan. We consider that the nucleation of a large earthquake is not entirely a mechanical process, but is closely related to the subduction dynamics and physical and chemical properties of materials in the crust and upper mantle; in particular, the arc magma and fluids.

Original languageEnglish
Pages (from-to)4-16
Number of pages13
JournalIsland Arc
Issue number1
Publication statusPublished - 2010 Mar 1


  • Arc magma
  • Fluids
  • Large earthquakes
  • Mantle wedge
  • Seismic tomography
  • Slab dehydration

ASJC Scopus subject areas

  • Geology


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