The alert status for Mayon Volcano was raised from level 2 to 3 on Thursday, June 8 due to an “increased tendency towards a hazardous eruption,” said the Philippine Institute of Volcanology and Seismology (Phivolcs).
In raising the alert level to 3, Phivolcs said that Mayon Volcano is “exhibiting magmatic eruption of a summit lava dome, with increased chances of lava flows and hazardous pyroclastic density currents (PDCs) affecting the upper to middle slopes of the volcano and of potential explosive activity within weeks or even days.”
Residents within the six-kilometer radius of the permanent danger zone should be evacuated due to the risk of PDCs, lava flows, rockfalls and other volcanic hazards, according to Phivolcs.
It also advised increased vigilance against pyroclastic density currents, lahars, and sediment-laden stream flows along channels draining the edifice.
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)
‘Increasing unrest’
“Since the alert level status was raised from Alert Level 1 to Alert Level 2 on June 5, 2023, repeated collapse of the growing summit dome of Mayon Volcano has generated an increasing number and volume of rockfall events,” Phivolcs said in a bulletin issued at 12 p.m.
Phivolcs recorded 267 rockfall events and two volcanic earthquakes between June 5 and June 8, from 54 rockfall events between June 1 and June 4.
“These events had durations of one to three minutes and transported lava debris within a kilometer's range of the southern upper slopes. The volume of discrete rockfall events increased on June 3 based on the seismic record, signaling an increase in the rate of dome growth,” it pointed out.
Phivolcs also observed three PDC events on the Bonga and Basud Gullies at 6:18 a.m., 9:53 a.m., and 11 a.m. on Thursday.
“The PDCs lasted four to five minutes based on the seismic record and emplaced within a kilometer of the summit crater,” it said.
Meanwhile, sulfur dioxide emission remains at baseline or background levels.
Phivolcs pointed out that the overall monitoring parameters indicate that “very slow extrusion of shallow degassed magma is ongoing and is incrementally increasing in rate; i.e., effusive magmatic eruption is taking place.”