Volcanic activity is intensifying on the island of Kuchinoerabu, in southwestern Japan.
At 10:30 AM on Wednesday, the Japan Meteorological Agency raised the volcanic alert level from 2 to the second-highest level of 4.
That means elderly and disabled people should be evacuated and everyone else should prepare to evacuate.
As of 3:00 PM, the agency had recorded 29 volcanic earthquakes.
The largest one had a magnitude of 1.9. Its focus was estimated to be about 5 kilometers underground, in almost the same location as a similar pre-eruption quake that struck 3 years ago.
The agency warns that an eruption powerful enough to cause serious damage to the island's residential areas is possible.
The warning is the first since eruptions in May 2015 prompted the evacuation of all residents.