1986 年伊豆大島火山噴火に伴う蒸気井のガスおよび温泉水の地球化学的変化

概要

論文の詳細を見る
Temporal variations in temperature and ^3He/^4He ratio of fumarolic gas emitted from a steam well located about 3 km NNE of the central cone of Izu-Oshima volcano have been monitored since October, 1986. Chemical compositions of hot spring waters collected at a well close to the steam well have also been measured since September, 1986. The temperature of the gas increased 5-6℃ after the eruptions of November, 1986, reached the maximum value in February-March in 1987 and then decreased gradually. The ^3He/^4He ratio was nearly constant (1.7-1.9 R_<atm>) before and immediately after the eruptions of November, began to increase in December and then has been keeping a constant value of 5 R_<atm> since May, 1987. These features are interpreted to be caused by the uprise of the magma. Concentrations of most chemical components in the hot spring water have also changed after the eruptions of November, 1986.
特定非営利活動法人日本火山学会の論文
1988-06-30