Thousands of people were reported to have fled their homes in the East Java district of Kediri when Mount Kelud erupted late on Thursday night.
The eruption shot a column of smoke 10 kilometers into the atmosphere, according to Surono, the former head of the Volcanology and Disaster Mitigation Center (PVMBG), as quoted by Viva.co.id, and sent gravel raining down as far as 50 kilometers from the crater of the volcano.
The eruption at 10:50 p.m. was preceded by a seismic earthquake was felt as far away as the Central Java town of Solo, the Jakarta Globe's Ari Susanto reported, and heard as far away as Yogyakarta, 200 kilometers away, according to Tempo.co.
Experts had warned that any eruption would be particularly explosive, given how quickly the volcanic activity had escalated at Kelud since Feb. 2. The eruption occurred less than two hours after authorities raised the alert to the highest level on the four-point scale, although residents had already begun evacuating since Thursday afternoon, MetroTVNews.com reported.
Sutopo Purwo Nugroho, a spokesman for the National Disaster Mitigation Agency (BNPB), told Republika.co.id that "thousands" of people had left the area and evacuation efforts were still ongoing.
He said authorities had imposed a 10-kilometer exclusion radius around the crater, double the five kilometers established earlier this week.
Supeno, the head of the East Java office of the National Search and Rescue Agency (Basarnas), told Viva.co.id that there were no reports yet of casualties as a result of the eruption, and that his office was focused on getting everyone out of the 10-kilometer exclusion radius.
The story continues to develop.