The Japan Meteorological Agency announced on Monday (August 4) that due to increased activity at the Mount Kusatsu-Shirane volcano spanning Gunma and Nagano prefectures, the volcanic alert level has been raised to Level 2. Entry restrictions have been implemented within a radius of about 1 kilometer around the Yugama Crater.
According to Japanese media reports, the Japan Meteorological Agency observed a sharp increase in volcanic earthquakes near the Yugama Crater of Mount Kusatsu-Shirane starting at 3 p.m. local time on Sunday (August 3). Within a 24-hour period until around 5 a.m. on Monday, a total of 40 earthquakes were recorded.
Furthermore, since around June of last year, there have been slow ground swelling changes in the shallow subsurface around Yugama, indicating a gradual intensification of volcanic activity.
Based on the observations mentioned above, the Japan Meteorological Agency has assessed that there is a possibility of an eruption at Mount Kusatsu-Shirane, which could have an impact on the surrounding areas. Therefore, at 5:50 a.m. on Monday, the volcanic alert level was raised from Level 1 “attention” to Level 2 “restriction around the crater.”
The agency has cautioned that within a radius of about 1 kilometer around the Yugama Crater, people need to be particularly vigilant against the possibility of large volcanic rocks accompanying an eruption. They urge the public to follow the instructions of local authorities and refrain from entering the danger zone. Additionally, during a volcanic eruption, volcanic ash fall and the risk of small rock fragments may occur downwind. Local residents are advised to stay alert and take preventive measures.
The agency also emphasizes that if volcanic activity continues to escalate, there is a possibility of further raising the alert level.
As of now, authorities have not issued evacuation orders for Kusatsu City and the nearby popular tourist destination of Kusatsu Onsen. However, volcanic activity is being closely monitored, and the potential impact on tourism is still under evaluation.
Mount Kusatsu-Shirane is an active volcano in Japan, standing at an elevation of 2,160 meters and is part of the Joshin’etsu Kogen National Park. Since a small-scale eruption and avalanche incident causing casualties occurred on January 23, 2018, the volcano has remained in an active state.