Mount Ruang erupted nearly half a dozen times in 24 hours beginning late Tuesday, stirring a spectacular mix of fiery orange lava, a towering ash column and volcanic lightning.
While officials said Ruang had started to calm Friday, authorities maintained the highest alert level of a four-tiered system, which indicates high volcanic activity.
Hundreds of locals on neighbouring Tagulandang island were seen cleaning up volcanic material from the harbour and their yards on Friday morning with the help of soldiers and police officers, according to an AFP journalist.
Some described their panic and rush to safety when the eruption began.
“I evacuated. There was a house. I stayed there. And then it rained and rocks fell. I prayed ‘God have mercy, please help me God’,” Ninice Hoata, a 59-year-old teacher, told AFP on Tagulandang.
White smoke of “medium to high intensity” was seen billowing up to 100 metres (328 feet) above the crater, Abdul Muhari, the national disaster mitigation agency (BNPB) spokesman said in a statement.
Other residents pleaded for more assistance.
“We really need tarpaulin assistance as soon as possible, to temporarily cover the leaking roof,” said Herman Sahoa, a 64-year-old Tagulandang resident.
“We are worried there will be a follow-up because there is information about that.”
– Thousands evacuated –
Elsewhere houses could be seen lying empty and the electricity was out in parts of the island, the journalist said.
Officials said Thursday communications had been knocked out on parts of both Ruang and Tagulandang island, which hosts around 20,000 people.
More than 6,000 residents of Tagulandang had been evacuated to the other side of the island that faces away from the crater, Joikson Sagunde, an official from the Sitaro islands disaster management agency, told AFP.
A day earlier authorities said they hoped to evacuate 11,000 people in the exclusion zone.
The closure of a nearby international airport in Manado city, more than 100 kilometres (62 miles) from the crater, was also extended to Friday evening, Abdul said.
The alert level upheld a six-kilometre (3.7-mile) exclusion zone around the crater, as well as warnings about further eruptions and parts of the volcano collapsing into the sea that could cause a tsunami.
In 2018, the crater of Mount Anak Krakatoa between Java and Sumatra islands partly collapsed when a major eruption sent huge chunks of the volcano sliding into the ocean, triggering a tsunami that killed more than 400 people and injured thousands.
Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire”.