Water Circulation System at Subduction Zones(＜Special Section＞The 60th Anniversary of VSJ “Latest Advances and Future Perspectives in Volcanology”)

• KATAYAMA Ikuo

  Department of Earth and Planetary Systems Science, Hiroshima University

Bibliographic Information

Other Title

• 沈み込み帯での水の循環様式(＜特集＞日本火山学会60周年「火山学の最新動向と今後の展望」)
• 沈み込み帯での水の循環様式
• シズミ コミ タイ デ ノ ミズ ノ ジュンカン ヨウシキ

Abstract

Water plays an important role for magma genesis and frictional properties; consequently, water circulation systems contribute to the variation of magmatic and seismic activity at subduction zones. Although subducting plate transports a large amount of water, most of water is released into the mantle via dehydration reactions at elevated temperature during subduction. Aqueous fluids released from the subducting plate then migrate along the plate boundary due to permeability anisotropy developed in the highly sheared serpentinite. Based on laboratory data, we estimated the fluid migration velocity to be〜7cm/year, which is close to the descending plate velocity, suggesting that polarity of water migration can be different in subduction systems. In northeast Japan, fluid migration velocity is slower than the subduction velocity, and hence water is transported downward into the deeper portions trapped by the mantle corner flow. In contrast, in southwest Japan where the fluid velocity is higher than the subduction velocity, water could be returned to the shallow regions along the subducting plate interface. This model can explain the seismic low velocity anomalies and geochemical signatures in these regions, in which the hydration of the plate interface is observed in shallow mantle wedge in southwest Japan, but is limited to the deeper parts of the mantle in northeast Japan. Water transported to deep levels could contribute to the active arc volcanism in northeast Japan, whereas water circulating at shallow levels in southwest Japan could trigger slow earthquakes due to fluid pressure build-up at the plate boundary.

Journal

• BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN

  BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN 61 (1), 69-77, 2016

  The Volcanological Society of Japan

Keywords

• water circulation
• subduction zone
• volcanic activity
• seismic activity
• permeability
• fluid velocity

Details

• CRID: 1390282679281211264
• NII Article ID: 110010051159
• NII Book ID: AN10512786
• DOI: 10.18940/kazan.61.1_69
• ISSN: 21897182
• ISSN: 04534360
• NDL BIB ID: 027212116
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I027212116
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • CiNii Articles
  • KAKEN
  • Crossref
• Abstract License Flag: Disallowed