Mayon Volcano continued to show “high-level unrest” with the occurrence of some dome collapse pyroclastic density current (PDC), rockfalls, and volcanic earthquakes during the 24-hour monitoring of the restive volcano in Albay, the Philippine Institute of Volcanology and Seismology (Phivolcs) said in its bulletin on Sunday, June 25.
Phivolcs defines effusive eruption as the outpouring of lava onto the ground, as opposed to explosive eruption, which is characterized by violent magma fragmentation.
“In the past 24-hour period, very slow effusion of lava from the summit crater of Mayon Volcano continued to feed lava flows and collapse debris on the Mi-isi (south) and Bonga (southeastern) gullies,” it said.
“The lava flows have advanced to revised approximate lengths of 1,300 meters and 1,200 meters along Mi-isi and Bonga gullies, respectively, from the summit crater while collapse[d] debris [has] deposited to 3,300 meters from the crater,” it added.
Phivolcs also observed 600-meter steam-laden plumes from the volcano.
The effusive eruption of Mayon Volcano produces lava, as seen in this photo taken on June 17, 2023. (ALI VICOY/MANILA BULLETIN)
Alert Level 3 stays
Mayon Volcano has been on Alert Level 3 since June 8, which means that there is a “relatively high level of unrest as magma is at the crater and hazardous eruption within weeks or even days is possible.”
According to Phivolcs, Mayon may maintain its alert status because it saw its current state to last for a few months, just like the eruption of the volcano in 2014.
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.
