Torishima is an active volcanic island located on the Izu Arc, 570 km south of Tokyo at Honshu island. The eruptive activity is divided into two stages; the stratovolcano stage, and the central cone stage. The eruption during the historic period in Torishima volcano has occurred in 1902, 1939, and 2002. We conducted landing observation of Torishima in May, 2004. Temperatures of the fumes and ground and compositions (CO2, SO2, H2S) Of volcanic gases were measured. The current activity of Torishima volcano is as follows: The highest temperature region showing appro)dmately 100°C is distributed along the narrow band inside the westside rim of Torishima caldera. The fume and ground temperatures at the north side in Io-yama, which is the central major cone of Torishima volcano are nearly constant at 100°C from 1957 to present. CO2 concentrations in volcanic gases from the fumaroles of the north side in Io-yama is in levels that have almost unchanged from 1965 to the present. A remarkable change of the fumarolic activity resulting from the eruption in 2002 was not detected in this observation.
|ジャーナル||Science Reports of the Kyushu University, Department of Earth and Planetary Sciences|
|出版ステータス||出版済み - 2 1 2005|
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