Manila - Philippine volcanologists Friday raised the alert level on a restive eastern volcano amid an increasing occurrence of low-frequency earthquakes. The Philippine Institute of Volcanology and Seismology warned residents not to wander into the seven-kilometre permanent danger zone around Mount Mayon in Albay province, 330 kilometres south-east of Manila.
"The number of recorded low frequency volcanic earthquakes rose to a higher level signifying possible movement of magma beneath the volcano edifice at shallow depth," the institute said.
Volcanologists also noted that the glow from Mayon's crater has intensified and was already visible in populated areas at the foot of the restive mountain.
The 2,472-metre Mayon is famous for its nearly perfect cone. It is one of the most active volcanoes in the country and its last major eruption was in September 2006.
Its deadliest eruption was in 1814 when it buried an entire town under ash and killed more than 1,300 people.