Mount Merapi volcano on Indonesia's Java island spewed ash 6 kilometres into the air on Friday, prompting authorities to raise the volcano ash advisory for aviation to red, an official said.
The eruption lasted for two minutes but there was no panic among nearby residents, said National Disaster Management Agency spokesman Sutopo Nugroho.
The aviation red alert means ash from the eruption could disrupt flights.
But Sutopo said the nearby Adisucipto international airport in the city of Yogyakarta was operating normally.
The alert level for the volcano itself remained at one notch above normal, he said.
A series of eruptions at Merapi killed more than 300 people in 2010.
Indonesia sits on the Pacific Ring of Fire, an area around the edges of the Pacific Ocean susceptible to earthquakes and volcanic eruptions.
The country is home to 130 active volcanoes.
