Not all have been abandoned, however.
In between eruptions, some villagers return to homes within an evacuation zone that runs to five to seven kilometers from the mountain's peak. There they scrape the build-up of heavy ash off their corrugated tin roofs and look for goods they can sell now that their harvests have been ruined by more than three months of incessant volcanic activity.
Others simply visit to escape the cramped evacuation centers set up in and around Kabanjahe, the highlands district headquarters around the volcano.
'They're cold and dirty,' said Tanda Stepo, a small farmer at a village less than four kilometers from the peak, who was forced to evacuate in November.
On a recent afternoon, he had little to do in the village, but milled about a junction where a neighbor kept a store open to sell basic goods and some food. When the mountain erupted, as it did a half dozen times that day, he watched the wind carry the ash just west of his village.
'I'm not scared,' he said, looking over fields of chilies and potatoes buried in five centimeters of gray ash. 'It's my village and I was born here. If the mountain erupts here, I'll die here.'
A police investigator visiting the village said people like Mr. Stepo were allowed to enter the evacuation zone only after signing a waiver acknowledging that they did so at their own risk.
So far, that hasn't changed, even after 15 people, mainly high school students, were killed during an eruption while venturing too close to the mountain over the weekend.
They were the first people to die due to volcanic activity since the mountain sprang alive last year. Authorities have since tightened access to the restricted zone, almost tripling the number of personnel on patrol and bringing in outsiders to discourage slack enforcement from officers who know villagers.
Villagers can continue to enter the evacuation zone, but only after obtaining a permit from a patrolling officer, according to Jhonson Tarigan, a local spokesman for the government relief effort. He suggested that some areas that posed the greatest danger–like the southeast flank that has been regularly torched by clouds of hot ash and gas–might be off limits in any event.
Last week almost 14,000 volcano refugees out of more than 30,000 were told they could return home. All come from villages that lie outside the evacuation zone but have experienced heavy ash fall.
Still, it appears few want to return home. On Monday, the number of people staying at shelters around the volcano was still rising to nearly 32,000, according to data from the district government. Many have slept on the floors of churches, mosques for months, with the less fortunate staying in wall-less event halls partially exposed to the wind and rain.
Rina Sitepu, a woman in her 50s whose village lies about three kilometers from Sinabung, last slept in her home three months ago. On a November morning following a night of steady tremors, military trucks had swooped into her village just as Sinabung erupted ash thousands of meters into the sky.
They pulled out of town with ash settling on neat crop rows of chilies and cabbage, and within hours a village of 2,500 was a ghost town, she said.
For now, most villagers can do little but look on and wait for the eruptions to cease, or to be relocated permanently.
Mrs. Sutepo, a Muslim, today lives with her husband at the largest mosque in Kabanjahe, where some 600 people have been living for up to three months.
She and her sisters-in-law said they had no complaints with the government's response to the disaster. But they bathe only every few days due to limited water supply, and sleep under unceasing lights for security reasons. All have lost weight despite three warm meals a day.
"It's just not as nutritious," Mrs. Sutepo said. 'And I haven't slept well."
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