Slab-derived fluids, fore-arc hydration, and sub-arc magmatism beneath Kyushu, Japan

Hiroto Saita, Junichi Nakajima, Takahiro Shiina, Jun Ichi Kimura

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We estimate the three-dimensional (3-D) P wave attenuation structure beneath Kyushu, Japan, using a large number of high-quality waveform data. Our results show that the mantle wedge is characterized by high-attenuation regions in the fore-arc corner and in the back-arc beneath volcanoes, with the two regions separated by a low-attenuation area. The volcanic gap in central Kyushu is underlain by low attenuation below the Moho. High attenuation in the fore arc is probably associated with serpentinized peridotite, while that in the back arc is interpreted as an upwelling flow that is the source of arc magmas. The presence of low-attenuation mantle that separates the high-attenuation hydrated, fore-arc, and back-arc mantle regions suggests that fluids are supplied from two depth levels of the slab by different mechanisms. Low attenuation beneath the volcanic gap probably results from intricate 3-D mantle flow that is caused by tectonic processes such as back-arc extension and ridge collision. Key Points The first study on P wave attenuation structure beneath Kyushu Characteristic attenuation structures associated with slab-derived fluids A volcanic gap controlled by the absence of a concentrated upwelling flow

Original languageEnglish
Pages (from-to)1685-1693
Number of pages9
JournalGeophysical Research Letters
Volume42
Issue number6
DOIs
Publication statusPublished - 2015 Mar 28

Keywords

  • intermediate-depth earthquakes
  • seismic attenuation
  • serpentine
  • upwelling flow

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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