Inflation and increased seismicity were detected at Ontakesan in February, causing JMA to raise the Alert Level.
Inflation ceased in late February and deformation rates had stabilized.
Seismicity continued to fluctuate, but decreased in mid-March and volcanic tremor ceased on 19 March.
No changes in emissions were observed on 4 June.
JMA lowered the Alert Level for Ontakesan to 1 (on a scale of 1-5) on 23 June.
Source: Japan Meteorological Agency (JMA)