Head of the Dieng Volcano Monitoring Command Post of the Volcanology and Geology Disaster Mitigation Center, Surip, said the phreatic explosion occurred at 12 a.m.
"The explosion spouted gas as high as 50 meters, reaching as far as the waterboom parking lot," he said. No seriously injured victims were immediately reported.
When the explosion took place there were about 10 tourists around the Sileri crater. The visitors were hit by mud.
But their condition were not serious and they are now taken to the nearest community health center in Batur.