Permalink : http://hdl.handle.net/2115/20429

JaLCDOI : 10.14943/gbhu.70.137

The energy source of volcanic activity is the heat of magma. Heat discharge rate on the initial stage of Usu 2000 eruptive activity was estimated to be around 1×109 J/sec, that was over one order higher than that on the initial stage of the 1977 activity, and comparable to its peak release rate observed after two years from the beginning of the eruptive activity. Compare to the 1977 activity, much shorter duration of the 2000 activity may be the result of rapid cooling of the intruded magma. Abundant ground water supplied from Lake Toya might remove the heat effectively through active vapor plume rise.