More lava spews as volcano's dome grows
"The new lava dome has grown about 60 meters, with volume from 300,000 cubic-meters a few days ago to one million cubic-meters now," said Dewi Sri of the volcanology office in Yogyakarta, the city closest to the volcano.
A lava dome is a mound-shaped growth resulting from the eruption of high-silica lava from a volcano that can become unstable leading to one of the most lethal forms of volcanic event.
Sulfurous smoke also billowed up 600 meters (yards) from the volcano's peak but this was not dangerous, Dewi Sri said.
Monitors have observed 24 lava trails flowing into a valley near the peak since Friday, she said Saturday.
"So far lava trails can still be held but we don't know until when. We'll have to wait," she said, saying that numerous lava trails would emit deadly heat clouds.
A new lava dome has been forming at the peak of Merapi over the past week, signalling that the eruption would involve an outflow of lava and deadly heat clouds rather than a massive explosion, scientists have said.
More than 5,000 people have fled their homes around the volcano after an alert was issued three weeks ago, although some are returning to their villages during the day to work.
Despite the growing lava dome, the status of the volcano remained unchanged Saturday, at one level below that which would require mandatory evacuation of thousands more living around its fertile slopes.
Despite warnings, many villagers have refused to relocate, fearing they may lose their property and cattle.
In its last large eruption in 1994, heat clouds known locally as "shaggy goats" careened down the volcano at more than 100 kilometres (60 miles) per hour, reaching temperatures of 600 degrees Celsius (1,100 degrees Fahrenheit).
The clouds killed some 66 people.
Indonesia sits on the Pacific "Ring of Fire" noted for its volcanic and seismic activity. The country has more than 100 active volcanoes.