The Philippine Institute of Volcanology and Seismology (Phivolcs) on Friday, June 9 warned of ash fall and possible lahar flow in areas surrounding Mayon Volcano.

In the past 24 hours, six dome-collapse pyroclastic density currents (PDC) that lasted three to six minutes and 199 rockfall events occurred in Mayon Volcano.

“The PDC and rockfall events emplaced lava debris on the southern gullies within two kilometers from the summit crater. Thin light brown ash from the rockfalls and continuous moderate degassing from the summit crater produced steam-laden plumes that were bent and drifted to the general south,” Phivolcs said in its 8 a.m. bulletin.

“Fair crater glow or ‘banaag’ and incandescent rockfall shed from new fluidal lava at the summit of Mayon Volcano were also observed last night (June 8),” it said.

IP camera footage of the pyroclastic density current, or PDC event, at 6:18 a.m., June 8, 2023. This was taken from the Mayon Volcano Observatory. (Phivolcs)

Phivolcs recommended the evacuation of residents within the six-kilometer permanent danger zone due to risk of PDCs, lava flows, rockfalls, and other volcanic hazards. 

It also advised increased vigilance against PDCs, lahars, and sediment-laden stream flows along channels draining the volcano edifice.

Phivolcs said that heavy rainfall could cause channel-confined lahars and sediment-laden stream flows in channels where PDC deposits were emplaced.

Likewise, it said that ash fall events may most likely occur on the south side of the volcano based on the current prevailing wind pattern.

Phivolcs advised civil aviation authorities to request that pilots refrain from flying close to the volcano because ash from sudden eruption may pose hazards to aircraft.

Mayon Volcano has been placed under alert level 3 on June 8, as it is “currently in a relatively high level of unrest as magma is at the crater and hazardous eruption is possible within weeks or even days.”