LEGASPI, Philippines, Dec 16, 2009 (AFP) - Lava poured down the Philippines' Mayon volcano Wednesday as experts warned it could erupt for months, meaning thousands of villagers will spend Christmas in crowded evacuation centres.
Five small explosions were detected from Mayon on Wednesday morning, the last of which shot ash 500 metres (1,640 feet) into the air, government volcanologist July Sabit told AFP.
"Lava flow and lava fragments rolling down the volcano are continuous," Sabit said.
"It is part of the eruptive activity of the volcano. There is a high probability it will be like this for months."
Sabit cited Mayon's last eruption in 2006, when it emitted ash and oozed lava for two months.
The eruptions of 2006 did not claim any lives, but left huge deposits of volcanic ash on Mayon's slopes.
When Typhoon Durian hit the same area in December 2006, it caused a landslide of volcanic ash that killed more than 1,000 people.
The government has already evacuated about 23,000 people living in farming villages near the foot of Mayon and hopes to evacuate another 20,000 this week.
Most of the evacuation centres are at government schools, where classes have been called off.
Raffy Valenzuela, the civil defence chief for Albay province, where Mayon is located, said the makeshift camps were not yet up to standard.
"Some (schoolhouses) don't have sufficient bathrooms, others have... no running water. We are still fixing these things because this evacuation has been very sudden," he said.
Chief volcanologist Renato Solidum said that in the "worst-case scenario" of a major eruption, the government might have to evacuate another 15,000 families, or roughly 75,000 people.
Military trucks and even heavy trucks intended for construction projects are being used to evacuate the residents, Solidum said.
The government is ready to forcibly evacuate all villagers within the danger zone but there has been no resistance so far, he added.
The Mayon threat has come at a particularly inconvenient time of the year for the evacuees as they, like most of the other 92 million people in the predominantly Christian country, prepare for Christmas celebrations.
Defence Secretary Norberto Gonzales, who is in charge of disaster preparations, conducted an aerial survey of the volcano using a military helicopter on Wednesday.
He promised to distribute thousands of face masks to villagers to protect them from the effects of any volcanic ashfall.
The Philippine Institute of Volcanology and Seismology raised the alert level for Mayon to three on Monday after lava was seen spewing from the crater, and evacuations began immediately.
Level three on the five-point scale means a hazardous eruption is likely in the very near future.
Mayon, which sits above a farming area about 330 kilometres (200 miles) southeast of Manila, has erupted 48 times since records began, claiming thousands of lives.
In 1814, more than 1,200 people were killed as lava buried the town of Cagsawa.
However the 2,460-metre (8,070-feet) volcano remains a popular tourist attraction, and is famous for its perfect cone.
The Philippines is part of the so-called Pacific "Ring of Fire" that is known for its volcanic activity. The Philippine volcanology institute lists 22 active volcanoes in the country.