LEGASPI, Philippines - Rumbling Mayon volcano in the Philippines is showing signs of becoming clogged with lava and could erupt explosively, a government volcanologist said Saturday.
The volcano, which has been oozing lava for weeks, is also emitting gas and ash, all signs of a powerful eruption any day now, said Ed Laguerta, head of the government's volcanology team monitoring Mayon.
"Mayon volcano is still in a high state of unrest and in the coming days it could still have an explosive eruption," he warned in a radio interview.
"The number of (volcanic) quakes have lessened but now the quakes are of a different variety. What is becoming clear is that it (the volcano) is getting clogged. That is when the lava is rising but cannot get out," he said.
"The edifice looks inflated so we cannot say that the actual activity of Mayon has decreased," he said.
"Just because the volcano looks calm... it does not mean its activity is decreasing. We cannot be off our guard. After this calm period, it could explode with even more force," Laguerta added.
The Philippine Institute of Volcanology and Seismology said it had kept Mayon on alert level four, meaning a hazardous eruption may occur within days.
It warned people to stay away from river channels and other areas that might possibly be hit by volcanic mudflow in the event heavy rain falls on Mayon.
The government has evacuated more than 47,000 people living around the volcano, about 330 kilometres (200 miles) southeast of Manila, since it began belching smoke and oozing lava earlier this month.
The evacuees are housed in 28 makeshift centres -- mostly government schools -- and could remain there for more than a month until the volcano settles, said Jukes Nunez, director of the disaster preparations office.
There are still a few people who refuse to leave the danger zone but Nunez said they were at the fringes of the zone and were not directly threatened.
However, he warned that the evacuees would need to find new shelters when schools reopen in January after the Christmas holidays.
Governor Joey Salceda, whose province includes Mayon, said in a television interview that he plans to set up a tent city for those who evacuated the area around the volcano.
The 2,460-metre (8,070-foot) volcano, which is famed for its near-perfect cone, has erupted 48 times in recorded history. In 1814, more than 1,200 people were killed as lava buried the town of Cagsawa.