MANILA — The Philippine Institute of Volcanology and Seismology (Phivolcs) raised Alert Level 2 over Mayon Volcano on Monday.
This amid the increase in rockfall from the volcano's summit lava dome indicating aseismic growth.
In its 10 a.m. bulletin, rockfall increased in frequency from an average of 5 events per day to 49 events per day, records from June 4 to 5 of 5:00 a.m. showed.
Based on data on May 9, it said Mayon Volcano's lava dome has increased in volume by approximately 83 cubic meters since February 3.
A total of 318 rockfall events have been recorded by the Mayon Volcano Network since April 1 while 26 volcanic earthquakes have been recorded for the same period, it added.
Alert Level 2 means that there is current unrest driven by shallow magmatic processes that could eventually lead to phreatic eruptions or even precede hazardous magmatic eruption, Phivolcs said.
State seismologists advised the public to be vigilant and refrain from entering the volcano's 6-kilometer-radius permanent danger zone to "minimize risks from sudden explosions, rockfall, and landslides."
"In case of ash fall events that may affect communities downwind of Mayon’s crater, people should cover their nose and mouth with [a] damp, clean cloth or dust mask," it added.
Mayon is located in Albay and is the most active of the Philippines' volcanoes. It last erupted in 2018.