Residents who had fled an area hit by the ash at the weekend have returned to their homes, with the volcano's status remaining on the second level of alert for a possible eruption.
"We never ordered the refugees to leave, but the clouds of dust scared them.
The dust gave them throat burn and respiratory problems," Julianto, an observer for the Department of Vulcanology, told Reuters on Tuesday.
"The volcano today, according to the seismograph, is acting normally, but its status is still one below the highest alert," added Julianto, who monitors the volcano at the Babadan post, 1,278 metres (4,193 feet) up the mountain.
The 2,968-metre (9,737 foot) mountain towers over the Central Java coastal plain, one of Indonesia's most densely populated areas and clearly visible from Yogyakarta, an old royal capital of two million people some 20 km (12.5 miles) away.
Glowing lava was clearly visible shortly after dawn on Tuesday before clouds shrouded the peak.
Sixty people were killed when Merapi erupted without warning in November 1994, while in January last year 8,000 people were evacuated when it poured out hot gas, ash and lava.
Villages closest to the peak were not affected by recent clouds of ash, which blew across them and spread up to 60 km (nearly 40 miles) to the west.
In the affected areas, everything is covered centimetres (inches) deep in fine volcanic ash: red-tiled roofs, coconut trees, banana bushes, vegetable crops and roads are a uniform grey. Villagers walk around with handkerchiefs or surgical masks to their noses, while vehicles stir up eddies of dust.
Medical doctor Edi Suharso said at the clinic in the town of Dukun -- the name means "witchdoctor" -- that 314 people were treated on Sunday for ailments such as breathing problems, eye and skin irritation and dizziness.
But only one person was admitted to hospital with an asthma attack.
At Ngargomulyo, eight km (five miles) from the summit, village chief Edi Warsono said people had been brought in from outlying hamlets about midday on Sunday over concern of an eruption.
They were thus prepared when the dust spewed out about three hours later, and 250 people were evacuated in 15 trucks to the district town as the dust drifted down. However, most of the 2,200 inhabitants of the village and surrounding hamlets remained.
Those who left returned on Monday morning.
"When it happened, it was quite dark. The dust was two to three centimetres (about an inch) thick on the ground. We couldn't see more than 10 metres (30 feet). It was almost like night," Warsono said.
He said the ash had caused a lot of damage to crops in his area. He calculated that 52 hectares (128 acres) of rice, 10 hectares (25 acres) of corn and 100 hectares 250 acres) of surface vegetables had been badly damaged.
Coconut trees and banana bushes had also been harmed.
"While Merapi is active, the activities of the village are virtually crippled because everyone is waiting for something to happen.
"We cannot send people into the fields if there is a possibility that they could be hurt by gas clouds," Warsono said.
Close to the summit, farmers were taking a fatalistic view of the danger.
Tobacco farmer Ngatiman said it was still possible to harvest his crop near the Babadan observation post. "But the ash has damaged many of the leaves and we will certainly get a lower price for it in the market," he said.
At Krinjing, the closest village to the peak, 20-year-old farmer Supardi said the village chief had ordered everyone to prepare for evacuation on Sunday, but the call to leave never came.
He also saw a positive side to the volcano.
"We will have problems with our crops this year. But the fertility of this land comes from the ash, and maybe it will be better next year," he said.
- Reuters - Thomson Reuters Foundation
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