Mount Merapi in photo taken from Bebeng villages in Yogyakarta, central Java, May 13 2006

Indonesia has raised the alert level for the Merapi volcano in central Java to the highest level. And the government has started evacuating the 34,000 people living on the slopes of the volcano, which is about 400 kilometers east of Jakarta.

Asnawarin Nasution, a scientist from the national volcanology center in Bandung, explains that the massive lava dome that crowns Merapi has been growing at an alarming rate.

"The dome [is] also already is becoming higher and higher, so we worried that something [would] happen," he said. "The dome already, I heard it [has] become one million cubic meters, and, every day, I heard it increase 150,000 cubic meters, nearly every day." 

Once the dome collapses, streams of lava, which scientists call pyroclastic flow, are expected to pour rapidly down the mountain's slopes via several rivers.

"There are several rivers that are sourced from the summit," said Asnawarin Nasution. "We worry that the pyroclastic flow, that is called wudus gendol, according to [the] local name, that we worried about the flowing down the river, because, maybe, you know, already, the height of the summit is 3,000 meters. It is a very, very steep slope, that also increases the speeding when the lava [is] coming down."

At one of several government evacuation centers near Merapi, government official Agnes Kurnia says that thousands began evacuating at 8 a.m. Saturday, when the alert was raised.

"So far 1,183 people have evacuated since this morning. We have not processed all, because more are still coming. We expect around 4,500," she said.

She points out that people fleeing the volcano could feel its heat, and that animals had started to panic, which locals believe is a sign of imminent eruption.

Merapi, one of more than 129 active volcanoes in Indonesia, began to show signs of life a few months ago. The mountain last erupted in 1994, sending out a searing cloud of gas that killed 60 people. In 1930, its largest eruption in recent memory, 1,300 people were killed.