THE Philippine Institute of Volcanology and Seismology (Phivolcs) has placed Mayon Volcano in Albay under Alert Level 1 after it exhibited unrest.
Level 1 means the volcano is “exhibiting abnormal conditions and has entered a period of unrest,” Phivolcs said in a bulletin issued at 4 p.m. yesterday.
Phivolcs said parameters monitored since July 30 last year when Mayon was placed under Alert Level “have been generally unremarkable.”
“However, daily visual and camera monitoring of the summit crater revealed that the lava dome emplaced towards the end of the 2018 eruption has undergone a change in morphology and slight extrusion by approximately 40,000 cubic meters between 6 June and 20 August 2022,” said Phivolcs.
It also said ground deformation observations “have tracked a slight short-term inflation of the volcano edifice,” particularly on the northwestern slope, since last April.
Phivolcs also said sulfur dioxide emission has increased to 688 tons a day as of August 12 or near baseline levels.
“Short-lived spikes in the number of low-frequency volcanic earthquakes were recorded on 26 May and 20 June 2022, but for most of this year, only baseline seismic activity has been detected,” said Phivolcs.
“These observation parameters indicate that volcanic gas-induced pressurization at the shallow depths of the edifice may be occurring, causing the summit dome of Mayon to be pushed out,” it added.
Phivolcs reminded the public to avoid entering the six-kilometer permanent danger zone due to risks of sudden steam-driven or phreatic eruption, rockfalls, avalanches and ash bursts.
“Furthermore, people living in valleys and active river channels are cautioned to remain vigilant against sediment-laden stream flows and lahars in the event of prolonged and heavy rainfall brought about by the advent of the rainy season,” Phivolcs added.