After Mount Semeru erupted on Saturday, killing scores of people on the slopes of Java island’s tallest peak, Indonesia’s volcanology agency is sending a team of specialists to identify regions too unsafe for residents to stay.

Questions have been raised in the days following the catastrophe concerning the efficiency of the disaster warning system and if some settlements should be relocated.

According to Ediar Usman, a Center for Volcanology and Geological Hazard Mitigation (PVMBG) expert, some regions are perhaps no longer safe to occupy.

“It’s not out of the question that a similar calamity may occur in the future,” he warned.

Eko Budi Lelono, who heads the geological survey centre, told Reuters the team would be sent this week and included experts from Yogyakarta who had studied the Merapi volcano near that city.

An estimated 8.6 million people in Indonesia live within 10 km of an active volcano, well within the range of deadly pyroclastic flows.

The magnitude of Saturday’s eruption caught many villagers off guard, with dozens unable to escape as the volcano projected an ash cloud kilometers into the sky, and sent dangerous pyroclastic flows into villages on the fertile slopes below.

At least 34 people were killed, with another 22 still missing, while thousands have been displaced, according to the disaster mitigation agency.

The eruption almost entirely buried some villages under meters of molten ash, with more than 100,000 homes partially damaged or destroyed.

Surveying the worst affected areas by helicopter on Tuesday, President Joko Widodo said that at least 2,000 homes would have to be rebuilt in different areas.

Semeru is one of more than 100 active volcanoes in Indonesia, which straddles the “Pacific Ring of Fire”, an area of high seismic activity that rests atop multiple tectonic plates.