stratovolcanoes 2171 m / 7,123 ft
Honshu (Japan), 36.62°N / 138.54°E
Eruption list: 2018, 1989, 1982-83, 1976, 1958, 1942, 1939, 1938(?), 1937, 1934, 1933(?), 1932, 1927, 1925, 1905, 1903(?), 1902, 1900, 1897, 1882, 1805
A small hydrothermal explosion likely occurred at Kusatsu-Shirane volcano on 7 February 1996.
Broken pieces of the ice sheet 20-30 cm in diameter were found washed ashore and discolored water was observed at the NW part of the lake. Probably, a sudden sudden discharge of fluid or a minor hydrothermal explosion was the cause.
A small eruption occurred from Yugama crater on 6 January 1989. It produced small amounts of volcanic ash on the frozen surface of the crater lake.
Kusatsu-Shirane volcano had 5 phreatic eruptions during 1982-83. Eruptions occurred on 26 October 1982, 29 December 1982, 26 July 1983, 13 November 1983, and on 10 December 1983. The water temperature at Yukama crater lake increased strongly and reached to 55.5 deg C after the first eruption, but did not increase further during the later eruptions.
(Source: GVP/monthly reports)
A phreatic eruption occurred at Mizugama Crater on 2 March 1976. A new crater 50 m in diameter and 10 m deep was formed in the NE part of Mizugama Crater.
The only event interrupting 34 years of quiet at Kusatsu-Shirane volcano between the eruptions in 1942 and 1976 was a small phreatic explosion in 1958.
An eruption occurred in 1942 and was unusual as it came from a different location than most activity at the volcano. A cluster of small craters was formed on the north flank of Mizugama Crater. A second group of craters formed on the south flank of Yugama Crater.
The largest historical eruption at Kusatsu-Shirane volcano was in 1932. It producing a 20 cm ash deposit reaching up to 2 km east of Yugama Crater.