- Associated Press - Tuesday, October 26, 2010

MOUNT MERAPI, INDONESIA (AP) - Pressure building beneath a lava dome in the mouth of Indonesia’s most volatile volcano could trigger one of its deadliest blasts in years, scientists warned Tuesday, as residents living along the slopes were moved to temporary camps.

Mount Merapi has seen increased volcanic activity in recent days and officials have raised the alert level for the 9,737-foot (2,968-metre) high mountain to its highest level, said government volcanologist Surono, who uses only one name.

It last erupted in 2006, when it sent an avalanche of blistering gases and rock fragments racing down the mountain that killed two people. A similar eruption in 1994 killed 60 people, while 1,300 people died in an eruption in 1930.

An avalanche of rocks spilled down Merapi’s trembling slopes before dawn Tuesday and gusts of hot ash shot 150 feet (50 meters) into the air as the mountain groaned and rumbled.

The greatest concern, Surono told reporters, was pressure building behind a massive lava dome that has formed near the tip of the crater.

“The energy is building up. … We hope it will release slowly,” he said. “Otherwise we’re looking at a potentially huge eruption, bigger than anything we’ve seen in years.”

While bracing for Mount Merapi to explode, officials were also trying to cope with the aftermath of a 7.7-magnitude earthquake on Monday that caused a tsunami off western Indonesia that left scores of villagers dead or missing. Indonesia, an island archipelago of 237 million people, is prone to earthquakes, tsunamis and volcanic activity due to its location on the so-called Pacific Ring of Fire.

Sri Purnomo, the head of Sleman district on Java island, where Mount Merapi is located, said officials were warning some 11,400 villagers living on the mountain’s southern slope to prepare for “urgent evacuation.”

Hundreds have already been relocated to makeshift camps set up at government buildings and sports fields more than six miles (10 kilometers) from the mountain’s base, most of them elderly residents and children.

“I just have to follow orders to take shelter here for safety even though I’d rather like to stay at home,” said Ponco Sumarto, 65, who arrived at one of the camps with her two grandchildren.

She said her children stayed at home to take care of their livestock and crops.

There are more than 129 active volcanoes to watch in Indonesia, which is spread across 17,500 islands and is prone to eruptions and earthquakes because of its location within the so-called “Ring of Fire” _ a series of fault lines stretching from the Western Hemisphere through Japan and Southeast Asia.

A 7.7-magnitude earthquake off Sumatra island late Monday, meanwhile, triggered a small tsunami that killed one farmer on a remote island and damaged more than 150 homes, said Ade Edward, a disaster management agency official.

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Associated Press writer Irwan Firdaus contributed to this report from Jakarta.