Mayon Volcano continued to show signs of heightened activity between Wednesday, June 21, and Thursday, June 22, recording a “very slow” lava effusion, 299 rockfall events, and eight dome-collapse pyroclastic density currents (PDCs), based on the monitoring of the Philippine Institute of Volcanology and Seismology (Phivolcs).
Phivolcs said in a bulletin released on Thursday that the effusive eruption of Mayon was still causing slow lava flows and collapsing debris in the Mi-isi and Bonga gullies on the south and southeast slopes, respectively.
Molten lava glows as it flows from the mouth of Mayon Volcano in this photo taken from Barangay Budiao in Daraga, Albay, on Saturday night, June 17, 2023 (Ali Vicoy/Manila Bulletin)
From the summit crater, the lava flows have advanced to “maximum lengths” of 2,500 meters and 1,800 meters along the Mi-isi and Bonga gullies, respectively, while collapsed debris has descended to a distance of 3,300 meters.
Eight dome-collapse PDCs lasted two to five minutes long.
According to Phivolcs, PDCs are mixtures of fragmented volcanic particles or pyroclastics, hot gases, and ash that rush down the volcaninc slopes or rapidly outward from a source vent at high speeds.
‘Hazardous’ eruption still possible
Phivolcs said that Mayon’s current state could last for a few months and its alert status could be maintained. It has been on alert level 3 since June 8.
However, it pointed out that Mayon is still in a “relatively high level of unrest as magma is at the crater and hazardous eruption within weeks or even days is possible.”
The evacuation of residents within the six-kilometer permanent danger zone has been recommended due to the risk of PDCs, lava flows, rockfalls, and other volcanic hazards.
Phivolcs warned the public to be cautious of PDCs, lahars, and sediment-laden stream flows along channels draining the volcano edifice.
It pointed out that heavy rainfall could cause channel-confined lahars and sediment-laden stream flows on 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 wind pattern.
Phivolcs advised civil aviation authorities to ask pilots to avoid flying close to the volcano because ash from sudden eruption may pose hazards to aircraft.
