JMA reported that increased eruptive activity at Asosan that began on 28 July continued at least through 13 August.
Ash plumes drifted N and NW, and crater incandescence was visible at night.
Sulfur dioxide gas emissions were very high at 2,000-5,000 tons per day.
The Alert Level remained at 2 (on a scale of 1-5).
Source: Japan Meteorological Agency (JMA)