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Geophysical Study on Hotspot Volcanisim in African Continent (Summary)

Research Project

Project/Area Number 07041079
Research Category

Grant-in-Aid for international Scientific Research

Allocation TypeSingle-year Grants
SectionField Research
Research InstitutionTohoku University

Principal Investigator

HAMAGUCHI Hiroyuki  Fac. Sci., Tohoku Univ. Prof., 理学部, 教授 (20004385)

Co-Investigator(Kenkyū-buntansha) AKUMBI M.  C.R.S.N., Zaire, Technician, 技術官
MAVONGA T.  C.R.S.N., Zaire, Reseracher, 研究員
WAFULA M.  C.R.S.N., Zaire, Reseracher, 研究員
ZANA N.  G.R.C., Zaire, Dirctor & Prof., 所長
NISHIMURA Takeshi  Fac. Sci., Tohoku Univ., Assoc. Res., 理学部, 助手 (40222187)
MORITA Yuichi  Fac. Sci., Tohoku Univ., Assoc. Res., 理学部, 助手 (30220073)
KASAHARA Minoru  Fac. Sci., Hokkaido Univ., Assoc. Prof., 理学部, 助教授 (40001846)
ISHII Hiroshi  Earthq. Res. Inst., Univ. Tokyo. Prof., 地震研究所, 教授 (30004386)
Project Period (FY) 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1995: ¥2,300,000 (Direct Cost: ¥2,300,000)
KeywordsAfrica / Rift System / Volcanic Activity / Eruption / Hotspot / Earth's Structure / Nyiragongo / Earthquake
Research Abstract

Although there are many hotspot volcanoes in the African plate, the Nyiragongo volcano in the eastern Zaire presents the highest potential threat to the local habitants. This potential has been recently much enhanced by (a) the starting volcanic eruptions at Nyiragongo on June 23,1994, and (b) the abnormal increasing population of about 1 million refugee fleeing from Rwanda on the middle of July, 1994. We have installed the seismo-volcanic monitoring systems around the volcano. Based on the instrumental observations, we showed that the seismic swarm activities have been high stages in the period between 1994 and 1996 and that they were located at the NE,NW and SE parts of Nyiragongo volcano. Recently, the number of felt earthquakes increased gradually around the volcanic area. We have continued to monitor the change of lava-lake level in the crater of Nyiragongo since August, 1994. We showed that the level of lava lake has ascending with a constant rate of 28 cm/day until July 1995 and that the supply rate of basaltic magma was estimated to be 2.2x10^5m^3/day. This ascend was stopped around October, 1995. The color of lake water in Kivulake changed at the northern part of the lake since February, 1996, which suggests the existence of submarine volcanic activity on the lake bottom. The above mentioned our observations clearly show that the present volcanic activity of Nyiragongo is still very active stages in all aspects.
We also investigated the heterogeneity and anisotropy in the inner core. The heterogeneity in the core was examined by using differential travel times of PKP(BC)-PKP(DF). The geographical pattern of the travel time residuals was found to be a manifestation of degree one heterogeneity in the outermost about 500 km of the inner core. Spherical harmonics analysis showed that the P velocities were fast in the region from 43゚ E to 177゚ E and slow in the region from 183゚ W to 43゚ E.Geophysical implications of this pattern are briefly discussed.

Report

(1 results)
  • 1995 Final Research Report Summary
  • Research Products

    (21 results)

All Other

All Publications (21 results)

  • [Publications] H.Hamaguchi: "Monitoring of Volcanic activity at Nyiragongo and Nyamuragira in eastern Zaire and their Volcanic hazard assesment" Periodica di Mineralojiea. 64. 33-34 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] T.Nishimura: "Estimation of Ishimoto-Iida's m-value for Seismic Source included in Volcanic tremors" Bull.Volcan.Soc.Japan. 40. 53-57 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] M.Kasereka: "Study of Seismic noise by STS-2 broad-band digital seismograph" Ind.Study IIESEE. 30. 147-162 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi: "Monitoring of Volcanic activity at Nyiragongo and Nyamuragira in eastern Zaire and their Volcanic hazard assesment" Rep.on Volca.Act.& Volca.Studies in Japan for the Period from 1991 to 1994. 57-59 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] S.Tanaka and H.Hamaguchi(研究協力者): "Degree one hetero geneity and hemispherical variation of anisotropy in the inner Core from PKP(BC)-(DF)" Jour.Geophys.Res.(投稿中). (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] N.Zana: "Macroseismic effects of the Kabalo earthquake in Zaire on September 11,1992" Bull.Seis.Soc.Amer.(投稿中). (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 浜口博之,森田裕一: "ニイラゴンゴ火山の溶岩湖" 科学. 65. 711-713 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 浜口博之: "東アフリカ地溝帯のニイラゴンゴ・ニアムラギラ火山の最近の噴火活動" 地学雑誌. 104. 625-626 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 浜口博之: "ニイラゴンゴ火山の噴火危機" 月刊アフリカ. 35. 4-7 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 浜口博之: "ザイールの火山観測体制と最近の活動" 「火山噴火予知連絡会20年のあゆみ」(気象庁). 239-241 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 浜口博之,森田裕一,他: "ザイール・ニイラゴンゴ火山の噴火活動と危機評価" 「'95国際火山ワークショップ報告」. 89-102 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi, Y.Morita, et al: "Monitoring of volcanic activity at Nyiragongo and Nyamuragira in estern Zaire and their volcanic hazard assessment." Periodico di Mineralogica. 64. 33-34 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] T.Nishimura: "Estimation of Ishimoto-Iida'sm-value for seismic source including in volcanic tremors" Bull. Volcan. Soc. Japan. 40. 53-57 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] M.Kasereka: "Study of seismic noise by STS-2 broad-band digital seismograph" Ind. St. IIESEE. 30. 147-162 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi: "Monitoring of volcanic activity at Nyiragongo and Nyamuragira in eastern Zaire and their volcanic hazard assessment" Per. on Volcan. Act. & Volcan. St. in Japan for 1991-1994. 57-59 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] S.Tanaka and H.Hamaguchi: "Degree one heterogeneity and hemispherical variation of anisotropy in the inner core from PKP(BC)-PKP(DF)" Jour. Geophys. Res. (submitted). (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] N.Zana, M Wafula, et al.: "Macroseismic effects of the Kabolo earthquake in Zaire on Sept II,1992." Bull. Seism. Soc. Amer.(submitted). (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi and Y.Morita: "Lava lake activity at Nyiragongo volcano" Kagaku. 65. 711-713 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi: "Recent volcanic activity of Nyiragongo and Nyamuragira in the East African rife valley" Jour. Geography. 104. 4-7 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi: "Volcanological observation network and recent colcanic activity in Zaire" "The 20th Anniver. Rep. of Cood. Comm. Pred. Volcan. Erupt.". 239-241 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] H.Hamaguchi, Y.Morita, et al.: "Eruptiva activity of Nyiragongo volcano and their hazard assessment." Rep. Intern. Wksp. Volcan. Commem. 50^<th> Anniver. Mt.Showa-Shinzann. 89-102 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary

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Published: 1995-04-01   Modified: 2016-04-21  

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