Precursory Events of Large-scale Caldera-forming Eruption -Examples at Kikai and Aira Calderas-

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Other Title
  • 大規模カルデラ噴火の前兆現象 −鬼界カルデラと姶良カルデラ−

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Description

The precursory events of caldera forming eruptions at Kikai and Aira calderas in Kyushu were investigated. Examples at Kikai caldera are 1) intermittent vulcanian eruptions of mafic magma for ca 8000 years, 2) sector collapse of the volcano, 3) eruption of degassed rhyolitic magma shortly before the climactic eruption, and 4) severe ground shaking occurred twice during the eruption. These pieces of evidence suggest, 1) the preceding long, dormant period is not necessary for a caldera-forming eruption, and 2) the trigger of the climactic eruption was not the mixing of coexisting mafic and felsic magmas, but was closely related to the decompression of felsic magma. We could not find any precursory event at Aira caldera, but if a steady uplift of 1.3 mm/year measured around the Aira caldera had continued since the 30 ka Aira eruption, felsic magma of several tens km3 volume would have already accumulated in the magma reservoir.

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Details 詳細情報について

  • CRID
    1050282676916977536
  • NII Article ID
    120002515150
  • NII Book ID
    AN00027784
  • ISSN
    0386412X
  • HANDLE
    2433/129400
  • Text Lang
    ja
  • Article Type
    departmental bulletin paper
  • Data Source
    • IRDB
    • CiNii Articles

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