• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Lake Nyos in dual agony-An assessment of the limnic eruption and dam collapse-

Research Project

Project/Area Number 16403012
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section海外学術
Research Field Geochemistry/Astrochemistry
Research InstitutionOkayama University

Principal Investigator

KUSAKABE Minoru  Okayama University, Institute for Study of the Earth's Interior, Professor, 地球物質科学研究センター, 教授 (20015770)

Co-Investigator(Kenkyū-buntansha) SATAKE Hiroshi  Toyama University, Faulty of Science, Professor, 理学部, 教授 (40134994)
KOBAYASHI Katsura  Okayama University, Institute for Study of the Earth's Interior, Associate Professor, 地球物質科学研究センター, 助教授 (20325129)
吉田 裕  吉田技術士事務所, 所長(研究職)
横山 哲也  岡山大学, 固体地球研究センター, 研究員(COE)
Project Period (FY) 2004 – 2005
Project Status Completed (Fiscal Year 2005)
Budget Amount *help
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 2005: ¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 2004: ¥7,100,000 (Direct Cost: ¥7,100,000)
KeywordsLake Nyos / Lake Monoun / Gas disaster / Limnic eruption / Crater lake / Age of Lake Nyos / Age determination / U-Th-Ra disequilibria / 湖の安定性 / CO_2 / U-Th-Ra非平衡
Research Abstract

The following results have been obtained through this geochemical studies on the limnic eruption at Lake Nyos and the age of Lake Nyos maar.
(1)Buildup_of_magmatic_CO_2_at_lakes_Nyos_and_Monoun_and_its_artificial_degassing : Lakes Nyos and Monoun have been known as notorious crater lakes, because they suddenly exploded in mid-80s, claiming about 1800 lives. Continuous observations since 1986 by the head investigator and his colleagues have demonstrated that the lakes are continuously charged by magmatic CO_2 of mantle origin, resulting in a steady increase in the amount of dissolved CO_2, and that recurrence of the limnic eruption followed by a gas disaster is highly likely at both lakes. Artificial degassing apparatus was installed at each lake in 2001-2003. However the degassing rate is not high enough to reduce the gas content to a safe level in several years. Thus danger of the recurrence of limnic eruption still remains.
In this study, we estimated the current rates of gas recharge … More and removal. Based on the estimate we have modeled the change with time in the CO_2 content of the lakes. It will take more than 30 years to make Lake Nyos safe. At Lake Monoun the gas content would become steady within several years under the current CO_2 recharge-removal rates. Fortunately additional degassing pipes were installed at Lake Monoun in 2006. If degassing pipes keep working, Lake Monoun would become safe in the near future. Lake Nyos still remains unsafe.
(2)Chronology of Lake Nyos dam : Lake Nyos is bound by a 45 m high natural dam at the north end. The dam consists of poorly consolidated pyroclastic materials that deposited at the time of the maar formation. It has been suggested that the dam is fragile and has been eroded away in a high rate since the formation of the lake. It may collapse in the near future. The dam collapse would result in a large scale flooding downstream which reaches Nigeria. In order to estimate the erosion rate, it is essential to obtain a reliable age of the maar formation. We have determined the age of the dam to be ca.5000 years B.P.using the U-Th-Ra dating method. This age is much older than 400 years obtained by the ^<14>C method and much younger than the K-Ar dates of ca.400 ka. Our new age would give an important constraint on the erosion rate of the dam. Less

Report

(3 results)
  • 2005 Annual Research Report   Final Research Report Summary
  • 2004 Annual Research Report
  • Research Products

    (9 results)

All 2006 2005 2004

All Journal Article (7 results) Book (2 results)

  • [Journal Article] Limnic eruption of Lake Nyos2006

    • Author(s)
      Kusakabe M.
    • Journal Title

      Institute for Study of the Earth's Interior, (Okayama University and Wizard CO.Ltd.) (DVD)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Degassing Lakes Nyos and Monoun : Defusing certain disaster2005

    • Author(s)
      Kling, G., Evans, W., Tanyileke, G., Kusakabe, M., Ohba, T., Yoshida, Y., Hell.J.V.
    • Journal Title

      Proceedings of the National Academy of Sciences, USA 102

      Pages: 14185-14190

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Degassing Lakes Nyos and Monoun - defusing certain disaster2005

    • Author(s)
      Kling, G., Evans, W., Tanyileke, G., Kusakabe, M., etc.
    • Journal Title

      Proceedings of the National Academy of Sciences of the USA 102

      Pages: 14185-14190

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Degassing Lakes Nyos and Monoun - defusing certain disaste2005

    • Author(s)
      Kling, G., Evans, W., Tanyileke, G., Kusakabe, M., etc.
    • Journal Title

      Proceedings of the National Academy of Sciences 106(印刷中)

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Symmetrical Helium isotope distribution on the Cameroon Volcanic Line, West Africa2004

    • Author(s)
      Aka, F.T., Nagao, K., Kusakabe, M., Sumino, H., Tanyileke, G., Ateba, B., Hell, J.
    • Journal Title

      Chemical Geology 203

      Pages: 205-223

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Some aspects of an on-line chromium redution method for D/H analysis of natural waters using a conventional IRMS.2004

    • Author(s)
      Itai, T., Kusakabe, M.
    • Journal Title

      Geochemical Journal 38

      Pages: 435-440

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Rare gases in mantle-derived rocks from Annbon Island : Preliminary step-heating helium results.2004

    • Author(s)
      Aka, F.T, Kusakabe, M., Nagao, K., Tanyileke, G., Nnange, J., Nfomou, N.
    • Journal Title

      Journal of the Cameroon Academy of Sciences 4

      Pages: 163-169

    • Related Report
      2004 Annual Research Report
  • [Book] カメルーン・ニオス湖における湖水爆発2006

    • Author(s)
      日下部 実
    • Publisher
      岡山大学地球物質科学研究センター、(株)ウィザード(DVD)
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Book] カメルーン・ニオス湖における湖水爆発2006

    • Author(s)
      日下部 実
    • Publisher
      岡山大学地球物質科学研究センター(DVD)
    • Related Report
      2005 Annual Research Report

URL: 

Published: 2004-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi