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Quaternary Volcano > Active Volcanoes > Kusatsu-Shirane
Kusatsu-Shirane Volcano   textgeologicmap3Dgeologicmap
Prediction of eruption, mitigation of hazard, and benefit of volcano

   All historically recorded activities of Kusatsu-Shirane Volcano are phreatic eruptions. Fumarolic activities discharging H2S and other volcanic gasses are also common. Those activities like it happened in 1982 would continue for many years to come. Automatic surveillance system was installed for H2S. Establishment of similar surveillance for volcanic eruption is hoped for to prevent hazard.

   Before the eruption of Mizugama in 1976, a warning signal in the form of changed chemical compositions of gas and lake water were detected. Also in radiant heat survey with infrared camera, heat anomaly at the point of explosion was detected 3 years before the explosion. Minor volcanic tremors were detected with phreatic eruption. In 1974 melted sulfur was discovered at the bottom of Yugama.

   Following the national project of prediction of volcanic eruptions, the Meteorological Agency installed seismograph near Mizugama in 1978 and started continuous monitoring. However, at the current state of knowledge, it is very difficult to predict eruption especially at the small scale phreatic eruptions such as occurring in Kusatsu-Shirane. Although the scale is small, here sightseers can approach to the edge of craters. Therefore a contingency plan is essential.

   On the other hand, in Kusatsu-Shirane Volcano area, many first grade hot spring resorts rich in hot water, favorable temperature and compositions are distributed including famous Kusatsu and Manza. Fumarolic activity in Sesshogawara as well as scenes of Yugama at summit area and beautiful sceneries of the area attract many sightseers and sportsmen all year round. Hot springs used to provide resources such as iron ore and sulfur which were mined.

   In recent years geothermal energy is attracting interest as new energy source. Already geothermal energy has been utilized to melt snow on the road in Kusatsu. In Ishizu district an exploration well has been drilled for utilization of geothermal energy.

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