Eruption Alert Level Raised for Mt. Kusatsu-Shirane, Gunma Pref., Japan; Caution Urged Over Rockfalls Within 1 Kilometer

The Yomiuri Shimbun

13:01 JST, August 4, 2025

The Japan Meteorological Agency said Monday it has raised the volcanic alert level for Mt. Kusatsu-Shirane in Kusatsu, Gunma Prefecture, from Level 1 to Level 2, prohibiting entry to areas near the mountain’s crater. This is the first level 2 alert since March 2021.

According to the agency, more than 40 volcanic earthquakes have occurred near Yugama, the lake in the volcano’s crater, since 3 p.m. on Sunday. The agency has determined that volcanic activity was increasing, prompting the elevation to Level 2, the second lowest point on a five-point scale.

The agency is urging caution against rockfalls involving large volcanic rocks, often associated with an eruption, within approximately 1 kilometer of the crater lake.