Scientists drill volcano to stop deadly deluge

BOTOLAN, Philippines (CNN) -- The draining of a volcanic lake in the Philippines to prevent a deadly deluge on a town of 40,000 residents below has begun.

Workers with high pressure water hoses have started blasting a notch into Mount Pinatubo's summit to breach the volcano's crater and drain the lake that could unleash mass floods on the area.

Scientists fear that the Philippines' rainy season from June until late October could shatter the volcano's upper walls unleashing flash floods, threatening human lives in the Botolan municipality.

AUDIO Journalist Cecilia Lazaro reports from Manila on the draining of Mt Pinatubo 1.43 Mb / 1 min WAV sound

But breaching the crater is a dangerous operation with a 20 percent chance of also releasing floodwaters that could sweep through 18 villages as far as 40 kilometers (25 miles) away, scientists said.

Many residents have already evacuated and dozens of trucks and buses stood by to take away others if flood waters approach.

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Hundreds of villagers, however, carried on with their lives, despite flood fears and an evacuation order.

Ash deposits

The volcanic lake was formed during the 1991 eruption of Mount Pinatubo, and rain water in past years has already filled the lake to only a few meters from the crater's rim.

Ash deposits from the 1991 eruption pose a further threat since these could mix with overflowing lake water and form an erosive volcanic mud known as lahar.

The Philippine government has spent more than $19.6 million to build a so-called mega-dike to prevent further lahar damage on towns along river channels.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said the operation would take several days, presuming the crater wall did not collapse during the operation -- an outcome they still said was a 20 percent chance.

"We are prepared for a worst-case scenario but we don't foresee any complications," General Melchor Rosales, executive officer of the National Disaster Coordinating Council, told CNN.

Refusing to leave

Scientists have dug an emergency canal through a wall of the crater to direct the waters down river channels and into the South China Sea.

About 2,000 people died when a crater-lake breached on the Casita volcano in Nicaragua in 1998 buried two villages in a matter of minutes.

Some 8,000 residents were moved Wednesday in dump trucks and buses and any other available means of transport to local schools serving as evacuation centers.

Food, clothing and medicine have been provided since two weeks ago, with the help of the social welfare department, Rosales said.

But disaster officials have been encountering pockets of resistance due to the reported lack of food and sanitation facilities at the temporary shelters.

Rosales said disaster officials "would have no choice" but to forcibly move those who resist evacuation, adding it was up to local officials to enforce a deadline.

"The point is to put everybody out of harm's way and it was a consensus that the evacuation was the best solution for everybody," Rosales said.

"They could go back home safely in a few days," he added.

Pinatubo last erupted in 1991 and showered cities as far as Manila 130 km (80 miles) away with sulphuric ash. More than 800 people died in that eruption, mostly from diseases in congested evacuation camps.