Nine eruptions Tuesday sent lava and searing gas tumbling out of Mount Sinabung in North Sumatra province, said Indonesia's disaster mitigation agency spokesman Sutopo Purwo Nugroho. The volcano started spitting clouds of gas and lava as high as 7,000 meters (23,000 feet) in the air late Monday, but no casualties were reported.
He said more than 19,000 people have been evacuated from villages in a danger zone 5 kilometers (3 miles) around the crater to temporary shelters since authorities raised the alert status for Sinabung to the highest level in November.
Gray ash covered villages, farms and trees as far as 70 kilometers (43 miles) southeast of the mountain.
The 2,600-meter (8,530-foot) Mount Sinabung has sporadically erupted since September. An eruption in 2010 killed two people and caught scientists off guard because the volcano had been quiet for four centuries.
Transportation Ministry spokesman Bambang Ervan said airlines had been notified to avoid routes near the mountain.
Mount Sinabung is among about 130 active volcanoes in Indonesia, which is prone to seismic upheaval due to its location on the Pacific "Ring of Fire," an arc of volcanoes and fault lines encircling the Pacific Basin.