JMA reported that at 2331 on 1 August an explosion at Suwanosejima?s Ontake Crater ejected blocks 400 m from the crater. Weather clouds prevented visual confirmation of an ash plume. Crater incandescence was sometimes visible at night. The number of volcanic earthquakes increased on 4 August and four explosions were recorded on 5 August. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)