A volcano has erupted on the same central Indonesian island devastated by an earlier earthquake and tsunami, prompting warnings for air services over volcanic ash in the air.

Mount Soputan in North Sulawesi province spewed ash nearly 20,000ft into the sky, although there have been no evacuation orders so far.

A graphic showing the location of the volcano
(PA Graphics)

A government volcanologist said it is possible the eruption was accelerated by the 7.5 magnitude earthquake which struck Central Sulawesi on Friday.

“It could be that this earthquake triggered the eruption, but the direct correlation has yet to be seen as there had been an increase in the Mount Soputan activity,” Kasbani, the head of Indonesia’s Vulcanology and Geology Disaster Mitigation agency, told online news portal Tempo.

Kasbani, who uses one name, said volcanic activity had been increasing at Soputan since August and began surging on Monday.

A giant plume of volcanic ash rises from Mount Soputan
A giant plume of volcanic ash rises from Mount Soputan (Hetty Andih/AP)

Nazli Ismail, a geophysicist at University of Syiah Kuala, Banda Aceh, on Sumatra island, stressed there is no concrete evidence to show the events are linked.

He said: “People talk about the butterfly effect. The concept is that when a butterfly flaps its wings, it can cause a catastrophe.

“So it is possible for the earthquake to trigger the volcano eruption, but it’s not conclusive. This needs to be further investigated.”

Mr Nazri said the Soputan volcano eruption is not surprising as Indonesia sits on the seismically active Pacific “Ring of Fire,” and Soputan is one of the most active volcanoes on the island.

The death toll from last week’s quake and tsunami has increased to 1,407.

Earthquake wreckage
Hundreds of people were killed in the quake and tsunami (AP)

National disaster agency spokesman Sutopo Purwo Nugroho said 519 of the bodies had been buried.

President Joko “Jokowi” Widodo has visited the city and said aid is now starting to arrive.

Indonesia is an archipelago of more than 250 million people and government seismologists monitor more than 120 active volcanoes.