Indonesian authorities on Wednesday issued a tsunami warning after Mount Ruang erupted, sending ash thousands of feet high.
Officials ordered more than 11,000 people to leave the area.
The Indonesian Center for Volcanology and Geological Disaster Mitigation said the volcano in northern Sulawesi island had at least five major eruptions in the past 24 hours.
Authorities have raised the volcano alert to the highest level.
There were no reports of deaths or injuries.
According to state authorities, at least 800 residents were evacuated from two villages on Ruang island to nearby Tagulandang island.
Indonesia, an archipelago of 270 million people, has 120 active volcanoes.
The country lies along the ‘Ring of Fire’, a horseshoe-shaped chain of seismic fault lines around the Pacific Ocean.
Volcanic activity has increased in Ruang following two earthquakes in recent weeks, the volcanology agency said on Tuesday.
Authorities urged tourists and others to stay at least six kilometers away from the 725-meter-high Ruang volcano.
Officials fear that part of the volcano could collapse into the sea and trigger a tsunami similar to the 1871 eruption there.
Hundreds of people had to evacuate after Mount Ruang erupted. (AFP: Center for Volcanology and Geological Hazard Reduction)
Hendra Gunawan, head of Indonesia’s volcanology agency, said in a statement that locals should “be alert to the possibility of rock eruptions, hot cloud releases and tsunamis caused by the volcano’s body collapsing into the sea.”
Tagulandang island to the northeast of the volcano is quite dangerous and its residents were among those asked to evacuate.
Indonesia’s National Disaster Mitigation Agency said people would be relocated to Manado, the nearest city, on Sulawesi island, a six-hour boat journey.
In 2018, the eruption of the Anak Krakatau volcano in Indonesia caused a tsunami along the coast of Sumatra and Java after part of the mountain fell into the sea, killing 430 people.