The Philippines' Mayon volcano turned up the heat with lava fountains and loud rumbling sounds Monday, and officials said it was getting closer to a major eruption that could come at any time.
Tens of thousands of villagers have been evacuated from the foothills as a precaution, but authorities are having trouble keeping them away from their homes and farms, said Gov. Joey Salceda of Albay province, about 210 miles southeast of Manila.
"There are people who have been evacuated three times and we sigh: 'You again?' " Salceda said. "We've been playing cat and mouse with them."
After a week of puffing out ash and sending bursts of lava trickling down its steep slopes, the 8,070-foot mountain overlooking the Gulf of Albay and Legazpi city in the central Philippines switched into high gear Monday with nearly 2,000 volcanic earthquakes and tremors since Sunday, state volcanologists said.
The emission of sulfur dioxide — an indication of magma rising inside the volcano — jumped to 6,000 tons per day from the normal 500, said the Philippine Institute of Volcanology and Seismology. It also reported "audible booming and rumbling sounds" in the eastern flank of the volcano, accompanied by intensified crater glow at night.
Lava fountains bursting from the cone-shaped volcano overnight rose 650 feet in the air, the institute said.
Scientists raised the alert level Sunday to one step below a hazardous eruption, saying one was possible within days. The only higher level is when a major eruption is already in progress.
Army troops and police added more patrols to enforce a five-mile exclusion zone around the mountain, Salceda said.
More than 40,000 residents were given sleeping mats and food inside school buildings, gyms and other emergency shelters, but some have still been spotted checking on their farms in the prohibited zone. Salceda said about 5,000 more villagers were being transported out of Mayon's danger zone, where scientists said red hot lava flows had reached three miles from the crater.
A major eruption could trigger pyroclastic flows — superheated gas and volcanic debris that race down the slopes at very high speeds, vaporizing everything in their path. More extensive explosions of ash could drift toward nearby towns and cities. The provincial capital of Legazpi is about nine miles away.
'Zero' probability of survival
In Mayon's other eruptions in recent years, pyroclastic flows had reached up to four miles from the crater, Salceda said.
"The probability of survival in an eruption is zero if you're in the danger area. The solution is obviously distance," he told The Associated Press.
Mayon last erupted in 2006, when about 30,000 people were moved. Another eruption in 1993 killed 79 people.
The first recorded eruption was in 1616 but the most destructive came in 1814, killing more than 1,200 people and burying a town in volcanic mud. The ruins of the church in Cagsawa have become an iconic tourist spot.
In 1991, Mount Pinatubo exploded in the northern Philippines in one of the biggest volcanic eruptions of the 20th century, killing about 800 people.