unleashed another powerful eruption Monday, spewing searing clouds of gas and ash thousands of feet into the air to the sound of a booming explosion. There were no immediate reports of new casualties.
On the other side of seismically charged country, a break in weather was helping rescuers get aid to victims of a tsunami that slammed into several remote islands, sweeping entire villages to sea.
The twin disasters, which occurred almost simultaneously one week ago, have together killed nearly 500 people.
Mount Merapi, among 20 mountains now rumbling and spitting out ash in Indonesia, is one of the world's most active.
The latest blast sent massive clouds of ash spilling nearly two miles down the northeastern slopes, said Subrandrio, who is monitoring the mountain that has already killed 38 people.
With the increase in activity in recent days, villagers had already been evacuated.
Surono, chief of the Center for Volcanology and Geological Hazard Mitigation, warned that heavy rain over the weekend increased the danger of another larger eruption because water falling into the fiery crater can create sudden vapor pressure in the lava dome.
More than 800 miles to the west, boats and helicopters were ferrying aid to the most distant corners of the Mentawai Islands, where some coastal communities were pounded by waves up to 18 feet high last Monday. The tsunami destroyed hundreds of homes, schools, churches and mosques.
A military helicopter evacuated badly injured survivors who had languished in an overwhelmed hospital with only paracetamol to ease their pain, said Ade Edward, a disaster management official. Among those evacuated was a baby girl born in a shelter after the tsunami and a 12-year-old girl with a life-threatening chest wound.
A C-130 transport plane, six helicopters and four motorized longboats were ferrying food and emergency supplies.
Relief efforts were brought to a complete stop Saturday by stormy weather and rough seas.
"We're really glad to finally see the relief workers, doctors and rescue teams able to reach devastated areas," Edward said, adding that two navy ships arrived Sunday with many more police and soldiers deployed to speed up relief efforts.
The tsunami death toll climbed to 450 on Monday with the discovery of dozens more bodies, said Nelis Zuliastri from the National Disaster Management Agency.
The fault that ruptured Monday, running the length of the west coast of Sumatra island, also caused the 9.1-magnitude quake that unleashed a monster tsunami around the Indian Ocean in 2004, killing 230,000 people in a dozen countries.