Mount Merapi volcano spews smoke as seen from Sidorejo village in Klaten, near the ancient city of Yogyakarta, on Wednesday. ((Beawiharta/Reuters) )

Indonesia's Mount Merapi erupted Wednesday with its biggest blast yet, shooting searing ash into the sky, and forcing the hasty evacuations of panicked villagers and emergency shelters near the base.

Meanwhile, a 6.1-magnitude earthquake hit waters off the eastern province of Papua Wednesday evening, far from the volatile volcano. The earthquake rattled several villages, but there was no known damage or casualties.

Soldiers loaded men, women and crying children into trucks as rocks and debris hurled in the air and down the volatile volcano's slopes. No new casualties were reported immediately after the booming explosion that lasted more than an hour.

"This is an extraordinary eruption, triple from the first" on Oct. 26, said Surono, a state vulcanologist.

Tens of thousands of villagers have been evacuated from Mount Merapi, one of the most active volcanoes in the world, since it began erupting just over a week ago, killing 38 people, most from severe burns.

The government widened the danger zone to 15 kilometres from 10 kilometres as the massive blast endangered places that had not been evacuated earlier, as well as refugee camps within that distance.


Villagers flee their homes following another eruption of Mount Merapi in Cangkringan, Yogyakarta, Indonesia on Wednesday. ((Slamet Riyadi/Associated Press))

"I [didn't] think of anything else except to save my wife and son. We left my house and everything," said Tentrem Wahono, 50, who lives in Kaliurang village, about 10 kilometres from the crater.

He and his family fled on a motorbike, "racing with the explosive sounds, like the searing ash chased us from behind."

The last eruption has raised Merapi's status to "crisis" condition, said Andi Arief, a special staff at the presidential office dealing with disaster and social assistance.

The volcano's initial blast on Oct. 26 occurred less than 24 hours after a towering tsunami slammed into remote islands on the western end of the country, sweeping entire villages to sea and killing at least 428 people.

In both cases, relief operations are expected to take weeks, possibly months.

Indonesia, a vast archipelago of 235 million people, is prone to earthquakes and volcanos because it sits along the Pacific Ring of Fire, a horseshoe-shaped string of faults that lines the Pacific.

More than 1,300 kilometres west of the volcano, helicopters and boats were delivering aid to tsunami survivors in the most distant Mentawai islands, which lies almost directly over the fault that spawned the 2004 Indian Ocean monster quake and wave.

There has been talk in recent days about relocating villagers away from vulnerable coastlines.

"I'm all for it," said Regen, who lives on Pagai Utara island and goes by one name. "We're all terrified now, especially at night, and wouldn't mind moving further inland."

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