Geochemical approach to estimate the rates of Lakes Nyos and Monoun degassing and the Nyos dam erosion

2008 Fiscal Year Final Research Report

• Project/Area Number: 19403014
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Geochemistry/Astrochemistry
• Research Institution: University of Toyama
• Principal Investigator: SATAKE Hiroshi University of Toyama, 理工学研究部(理学), 教授 (40134994)
• Co-Investigator(Kenkyū-buntansha): KUSAKABE Minoru 富山大学, 理学部, 客員教授 (20015770) ; OHBA Takeshi 東京工業大学, 火山流体研究センター, 准教授 (60203915)
• Project Period (FY): 2007 – 2008
• Keywords: 自然災害 / 防災 / 地球化学 / 流体 / 国際貢献

Research Abstract

本研究期間中に行われたニオス湖とマヌーン湖(カメルーン)の水質調査から、マヌーン湖ではCO_2のガス抜きがほぼ終了に近づきつつあり、ニオス湖ではガス抜き開始前のCO_2量の約70%が残存していることが判明した。ニオス湖ではさらなるガス抜きが必要である。ニオス湖北岸の天然ダムのU-Th-Ra年代は4000年前後であった。この年代測定結果から、ダム侵食速度は15mm/年程度であり、近未来におけるダム崩壊の可能性は低いと判断される。

Research Products

• [Journal Article] Cosmogenic helium and neon in mantle xenoliths from the Cameroon Volcanic Line (West Africa) : preliminary observations (2009)
  • Author(s): F.T. Aka, M. Kusakabe, K. Nagao, J. Nni, G. Tanyileke, R. Ubangoh, B. Ateba and J. Hell
  • Journal Title: J. African Earth Sciences (in press)
• [Journal Article] Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing (2008)
  • Author(s): M. Kusakabe, T. Ohba, Issa, Y. Yoshida, H. Satake, T. Ohizumi,W.C. Evans, G. Tanyileke and G.W. Kling.
  • Journal Title: Geochemical Journal 42 Pages: 93-118
• [Journal Article] U-series dating of Lake Nyos maar basalts, Cameroon (West Africa) : Implications for potential hazards on the Lake Nyos dam (2008)
  • Author(s): F.T. Aka, T. Yokoyama, M. Kusakabe, E. Nakamura, G. Tanyileke, B. Ateba, V. Ngako, J. Nnange and J. Hell
  • Journal Title: J. Volcanol. Geotherm. Res. 176 Pages: 212-224
• [Journal Article] Temporal changes in the chemistry of lake water within Yugama Crater, Kusatsu- Shirane Volcano, Japan : Implications for the evolution of the magmatic hydro- thermal system (2008)
  • Author(s): T. Ohba, J. Hirabayashi and K. Nogami
  • Journal Title: J. Volcanol. Geotherm. Res. 178 Pages: 131-144
• [Presentation] Improving monitoring techniques of Lakes Nyos and Monoun (Cameroon) (2008)
  • Author(s): Issa, Y. Yoshida, M. Kusakabe, T. Ohba, H. Satake, and G. Tanyileke.
  • Organizer: 3^<rd> Asia-Africa Science Platform Program (AASPP) international seminar
  • Place of Presentation: ISEI, Okayama University at Misasa
  • Year and Date: 2008-03-22
• [Presentation] Evolution of CO_2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing (2008)
  • Author(s): M. Kusakabe, T. Ohba, Issa, Y. Yoshida, H. Satake, T. Ohizumi,W.C. Evans, G. Tanyileke and G.W. Kling
  • Organizer: 3^<rd> Asia-Africa Science Platform Program (AASPP) international seminar
  • Place of Presentation: ISEI, Okayama University at Misasa
  • Year and Date: 2008-03-22
• [Presentation] A new method for measuring CO_2 concentration in gassy lakes (2008)
  • Author(s): Y. Yoshida
  • Organizer: 3^<rd> Asia-Africa Science Platform Program (AASPP) international seminar
  • Place of Presentation: ISEI, Okayama University at Misasa
  • Year and Date: 2008-03-22
• [Presentation] Measuring U-Th-Ra diseauilibria and major-trace elements in basalts from Lake Nyos maar, Cameroon (West Africa) : What does it tell us about the age of Lake Nyos dam and associated hazards? (2008)
  • Author(s): F.T. Aka, T. Yokoyama, M. Kusakabe, E. Nakamura, G. Tanyileke
  • Organizer: 3^<rd> Asia-Africa Science Platform Program (AASPP) international seminar
  • Place of Presentation: ISEI, Okayama University at Misasa
  • Year and Date: 2008-03-22
• [Presentation] The role of the Cameroon Volcanic Line on ground water characteristics in the Mayo-Tsanaga river basin, far north Cameroon (2008)
  • Author(s): W.Y. Fantong, H. Satake, S.N. Ayonge and G.T. Mafany
  • Organizer: 3^<rd> Asia-Africa Science Platform Program (AASPP) international seminar
  • Place of Presentation: ISEI, Okayama University at Misasa
  • Year and Date: 2008-03-22
• [Presentation] Over two decades of CO2 and conductivity profiles change at Lakes Monoun and Nyos (Cameroon) (2007)
  • Author(s): Issa, T. Ohba, M. Kusakabe, Y. Yoshida, H. Satake, T. Ohizumi,W.C. Evans, G.W. Kling and G. Tanyileke
  • Organizer: Cities on Volcanoes 5
  • Place of Presentation: Shimabara, Kyushu, Japan.
  • Year and Date: 20071119-23
• [Remarks] Kusakabe, M. (2007) CTD and CO2 data (1986-2007) of Lakes Nyos and Monoun, Cameroon. Geochemical Journal Data-base, TERRAPUB
  • URL: http://www.terrapub.co.jp/journals/GJ/archives/