| Research Abstract |
Four active volcanoes, Turumi-dake volcano, kuju volcano, Aso volcano and Unzen volcano, are situated in the Central Kyushu, Japan. We have investigated eruption history of the volcanoes. The results of this study are as follows ;
1. The sequence of the growing of lava dome was watched and described as a member of Geological Party, Joint University Research Group for Unzen Volcano.
The Geological map of Unzen Volcano will be published by Geological Survey of Japan in the end of this fiscal year.
2. Blown down and burnt big trees by the Aso-4 pyroclastic flow were found at about 90 km from the Aso caldera. The occurrence of these trees was very informative for the estimation of temperature and velocity of the Aso-4 pyroclastic flow at distant area.
The mode of eruption of Naka-dake, Aso volcano, for the past 15,000 years are clarified. From this result, tentative hazard maps of Naka-dake were proposed.
3. The field evidence of the phreatic explosions of Tsurumi-dake in the period younger than 6,300 years was obtained around the foot of the volcano.
Some of the results of this investigation were orally presented on some meetings of academic society.
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