Mechanism and rate of magma degassing : Toward an understanding of bifurcation of explosive-effusive silicic volcanism

• Project/Area Number: 21684025
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Solid earth and planetary physics
• Research Institution: Tohoku University
• Principal Investigator: OKUMURA Satoshi 東北大学, 大学院・理学研究科, 助教 (40532213)
• Project Period (FY): 2009 – 2011
• Project Status: Completed (Fiscal Year 2011)
• Budget Amount: ¥22,490,000 (Direct Cost: ¥17,300,000、Indirect Cost: ¥5,190,000); Fiscal Year 2011: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2010: ¥12,090,000 (Direct Cost: ¥9,300,000、Indirect Cost: ¥2,790,000); Fiscal Year 2009: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
• Keywords: 火山現象 / 火山噴火 / マグマ / 脱ガス / 爆発的噴火 / 変形実験 / X線ラジオグラフィー

Research Abstract

A factor controlling the style and explosivity of volcanic eruptions is magma degassing during its ascent in a volcanic conduit. To understand the mechanism of the degasing and determine the degassing rate, we experimentally simulated magma ascent and observed in situ the deformation of magma by using originally developed deformation apparatus which was built up on synchrotron radiation X-ray imaging system in SPring-8. The experimental results demonstrated that the degassing rate from flowing magma was high. This result implies that some unknown mechanisms inhibit the degassing for explosive volcanism.

Research Products

• [Journal Article] The H_2O content of andesitic magmas from three volcanoes in Japan, inferred from the infrared analysis of clinopyroxene (2011)
  • Author(s): Satoshi Okumura
  • Journal Title: The European Journal of Mineralogy Volume: 23 Pages: 771-778
  • Peer Reviewed
• [Journal Article] Shear deformation experiments on vesicular rhyolite: Implications for brittle fracturing, degassing, and compaction of magmas in volcanic conduits (2010)
  • Author(s): Okumura, S., M. Nakamura, T. Nakano, K. Uesugi, A. Tsuchiyama
  • Journal Title: Jour. Geophys. Res Volume: VOL.115 Issue: B6 Pages: 6201-6201
  • DOI: 10.1029/2009jb006904
  • Peer Reviewed
• [Journal Article] Magma deformation may induce non-explosive volcanism via degassing through bubble networks (2009)
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Shingo Takeuchi, Akira Tsuchiyama, Tsukasa Nakano, Kentaro Uesugi
  • Journal Title: Earth Planetary Science Letters Volume: 281 Pages: 267-274
  • Peer Reviewed
• [Journal Article] Three differentiation stages of a single magma at Piton de la Fournaise volcano(Reunion hot spot) (2009)
  • Author(s): Vincent Famin, Benoit Welsch, Satoshi Okumura, Patrick Bachelery, Satoru Nakashima
  • Journal Title: Geochemistry Geophysics Geosystems Volume: 10 Issue: 1
  • DOI: 10.1029/2008gc002015
  • Peer Reviewed
• [Journal Article] Magma deformation may induce non-explosive volcanism via degassing through bubble networks (2009)
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Shingo Takeuchi, Akira Tsuchiyama, Tsukasa Nakano, Kentaro Uesugi
  • Journal Title: Earth Planetary Science Letters 281 Pages: 267-274
  • Peer Reviewed
• [Journal Article] Three differentiation stages of a single magma at Piton de la Fournaise volcano(Reunion hot spot) (2009)
  • Author(s): Vincent Famin, Benoit Welsch, Satoshi Okumura, Patrick Bachelery, Satoru Nakashima
  • Journal Title: Geochemistry Geophysics Geosystems 10
  • Peer Reviewed
• [Journal Article] Experimental constraints on permeable gas transport in crystalline silicic magmas
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Tsukasa Nakano, Kentaro Uesugi, Akira Tsuchiyama
  • Journal Title: Contribution to Mineralogy and Petrology Volume: (in press)
  • Peer Reviewed
• [Presentation] 間隙圧オシレーション法を用いた高温高圧下でのマグマの浸透率測定 (2011)
  • Author(s): 奥村聡・岡崎啓史・片山郁夫
  • Organizer: 日本火山学会2011年度秋季大会
  • Place of Presentation: 旭川
  • Year and Date: 2011-10-02
• [Presentation] 珪長質マグマ内でのガス移動メカニズム:脆性破壊に伴う亀裂形成のその場観察 (2011)
  • Author(s): 奥村聡・中村美千彦・上杉健太朗・中野司
  • Organizer: 日本鉱物科学会2011年年会・総会
  • Place of Presentation: 水戸
  • Year and Date: 2011-09-11
• [Presentation] 発泡したマグマの流動・変形その場観察 (2011)
  • Author(s): 奥村聡・中村美千彦・上杉健太朗・中野司・土山明
  • Organizer: 日本地球惑星科学連合2011年度大会
  • Place of Presentation: 幕張
  • Year and Date: 2011-05-24
• [Presentation] 剪断変形したマグマ中の気泡組織とガス浸透率の異方性 (2011)
  • Author(s): 奥村聡・中村美千彦・中野司・上杉健太朗
  • Organizer: 日本地球惑星科学連合2011年度大会
  • Place of Presentation: 幕張
  • Year and Date: 2011-05-24
• [Presentation] Evolution of microstructure of bubbles and gas permeability in sheared rhyolite (2010)
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Takuma Fujioka, Akira Tsuchiyama, Shingo Takeuchi, Tsukasa Nakano, Kentaro Uesugi
  • Organizer: 2010 American Geophysical Union Fall Meeting
  • Place of Presentation: San Francisco, USA
  • Year and Date: 2010-12-17
• [Presentation] プチスポット火山からの炭素放出量の見積もり (2010)
  • Author(s): 奥村聡・平野直人
  • Organizer: 日本火山学会2010年度秋季大会
  • Place of Presentation: 京都市
  • Year and Date: 2010-10-11
• [Presentation] 珪長質マグマからの開放系脱ガス (2010)
  • Author(s): 奥村聡・中村美千彦・土山明・中野司・竹内晋吾・上杉健太朗
  • Organizer: 日本鉱物科学会2010年年会・総会
  • Place of Presentation: 松江
  • Year and Date: 2010-09-25
• [Presentation] Experimental constraints on the permeable gas transport in ascending magmas (2010)
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Tsukasa Nakano
  • Organizer: G-COE symposium 2010 : Dynamic Earth and Heterogeneous Structure
  • Place of Presentation: Sendai
  • Year and Date: 2010-07-15
• [Presentation] 結晶を含むマグマ中の気泡組織とガス浸透率:減圧発泡実験からの制約 (2010)
  • Author(s): 奥村聡・中村美千彦・上杉健太朗
  • Organizer: 日本地球惑星科学連合2010年度大会
  • Place of Presentation: 幕張
  • Year and Date: 2010-05-23
• [Presentation] Shear deformation experiments on vesicular rhyolite : Implication for brittle fracturing, degassing, and compaction of magmas (2009)
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Tsukasa Nakano, Kentaro Uesugi, Akira Tsuchiyama
  • Organizer: 2009 American Geophysical Union fall meeting
  • Place of Presentation: San Francisco, USA
  • Year and Date: 2009-12-14
• [Presentation] Shear deformation experiments on vesicular rhyolite : Implication for brittle fracturing, degassing, and compaction of magmas (2009)
  • Author(s): Satoshi Okumura, Michihiko Nakamura, Tsukasa Nakano, Kentaro Uesugi, Akira Tsuchiyama
  • Organizer: 2009 AGU fall meeting
  • Place of Presentation: San Francisco, USA