State seismologists on Thursday raised Alert Level 3 over Mayon Volcano amid an “increased tendency towards a hazardous eruption.”

”This means that Mayon is exhibiting magmatic eruption of a summit lava dome, with increased chances of lava flows and hazardous PDCs (pyroclastic density current) affecting the upper to middle slopes of the volcano and of potential explosive activity within weeks or even days,” state-run PHIVOLCS said in its latest bulletin.

PHIVOLCS said a total of 267 rockfall events and two volcanic earthquakes were recorded between June 5, when Alert Level 2 was raised, and June 8, compared to 54 rockfall events from June 1 to 4.

”These events had durations of one to three minutes and transported lava debris within a kilometer range of the southern upper slopes,” it said.

The agency recommended that the six-kilometer-radius Permanent Danger Zone (PDZ) be evacuated due to the danger of PDCs, lava flows, rockfalls, and other volcanic hazards.

Civil aviation authorities were also asked to advise pilots to avoid flying close to the volcano’s summit, as ash from any sudden eruption can be hazardous to aircraft.

”Based on the current prevailing wind pattern, ash fall events may most likely occur on the south side of the volcano,” PHIVOLCS said.