東北日本上部マントルの部分溶融域のマッピング : 島弧におけるマグマの上昇

• 佐藤 博樹

  大阪大学理学部宇宙地球科学科

• 長谷川 昭

  東北大学理学部地震予知・噴火予知観測センター

書誌事項

タイトル別名

• Mapping of Partial Melt Zones in the Upper Mantle Beneath Northeastern Japan : Ascent of Magma in Island Arc
• トウホク ニホン ジョウブ マントル ノ ブブン ヨウユウイキ ノ マッピング

抄録

From the seismic velocity structure of northeastern Japan, we have mapped the regions of partial melt in the mantle wedge beneath the island arc. Massive partial melting, that supplies magma to the crust and the volcanoes, is found to exist beneath the volcanic front and downwards to the west. Extensive melting occurs at ～90 km, ～65 km and ～40 km depths, and most extensive beneath the Moho at the volcanic front (up to 3 vol. % partial melt). The melt staying underneath the Moho may cause melting of lower-crustal materials and produce felsic magma. Fractional crystallization may also proceed in the melting regions at the volcanic front. It is observed that mid-crustal S-wave reflectors exist in between the partial melting and volcanoes, and that low-frequency microearthquakes occur right above the melting regions. We suggest that magma movement in the ductile lower-crust causes low-frequency microearthquakes, and that magma penetration from the ductile lower-crust to the brittle upper-crust produces mid-crustal reflectors.

収録刊行物

• 火山

  火山 41 (3), 115-125, 1996

  特定非営利活動法人 日本火山学会

詳細情報

• CRID: 1390001204304747648
• NII論文ID: 110003041473
• NII書誌ID: AN10512786
• DOI: 10.18940/kazan.41.3_115
• ISSN: 21897182
• ISSN: 04534360
• NDL書誌ID: 4085516
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4085516
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可