It will not be as massive like the 1991 Mount Pinatubo eruption, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Tuesday on the restive Mayon Volcano.
"Hindi pwede 'yun dahil ang composition ng (Mount) Pinatubo ay kakaiba sa composition ng magma sa ilalim ng Mayon Volcano," Phivolcs director Renato Solidum said in an interview over Bandila DZMM.
The 1991 Mount Pinatubo eruption killed at least 847 people, displaced nearly 250,000 families, and caused P12.5 billion worth of damage to properties, agriculture, and infrastructure.
According to the Phivolcs' latest bulletin, Mayon Volcano is under Alert Level 3 "with relatively high level of unrest as magma is at the crater and hazardous eruption is possible within weeks or even days."
It could only be lava flow, but volcanologists observed an increase in the sulfur dioxide emission from the Mayon Volcano as of Tuesday, Solidum said.
Heavy rains, he said, could also threaten to bring down lahar or mudflows to communities and waterways.
As thousands of residents have already been evacuated, Solidum urged locals to not enter the six kilometer-radius permanent danger zone and seven-kilometer extended danger zone on the southern flanks due to danger of rockfalls, sudden explosion, or dome collapse.
The public is also advised to use dust masks or cover their nose and mouth with damp cloth in case of ashfall.
Asked how often the Mayon Volcano erupts, Solidum said there is no fixed interval.
The volcano last erupted in 2014. In the third millennium, it had eruptions in 2009, 2006, 2004, 2003, 2001.
Its most destructive eruption was in Feb. 1841 that buried a town and killed 1,200 people, records from Phivolcs showed.
"Ang importanteng intindihin ng ating mga kababayan ay madalas sumabog ito o kahit pumuporma lang na sasabog, 'yung mga nasa loob ng six-kilometer permanent danger zone ay talagang kailangan i-evacuate," he said.
Renowned for its near-perfect cone, Mayon Volcano is the most active among the 24 volcanoes in the Philippines, Solidum said.