A volcano erupted on Wednesday on the same central Indonesian island as an earlier earthquake and authorities warned planes about volcanic ash in the air.
Mount Soputan in North Sulawesi province spewed ash 6 000m into the sky on Wednesday morning.
The eruption status was raised from an alert to standby 4km from the summit and up to 6.5km to the west-southwest. Standby status means the public should avoid the area nearest the volcano and have masks available in the event of ashfall.
No evacuations were immediately ordered.
Planes were warned of the ash clouds because volcanic ash is hazardous for plane engines.
Soputan is on the northern part of Sulawesi island, where a central region was severely damaged by an earthquake and tsunami on Friday.
Indonesia, an archipelago of more than 250 million people, sits on the Pacific "Ring of Fire" and is prone to earthquakes and volcanic eruptions. Government seismologists monitor more than 120 active volcanoes.