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.  The lava flows have advanced to maximum lengths of one thousand five hundred (1500) meters from the summit crater while collapse debris have deposited to three thousand three hundred (3300) meters from the crater. A total of  nine (9) dome-collapse pyroclastic density currents (PDC) that lasted two (2) to four (4) minutes, two-hundred eighty (280) rockfall events, and two (2) volcanic earthquakes were recorded by the Mayon Volcano Network. Continuous moderate degassing from the summit crater produced steam-laden plumes that rose 100 m before drifting to the general west. Sulfur dioxide (SO2) emission averaged 978 tonnes/day on 16 June 2023. Short-term observations from EDM and electronic tiltmeter monitoring show the upper slopes to be inflating since February 2023. Longer-term ground deformation parameters based on EDM, precise leveling, continuous GPS, and electronic tilt monitoring indicate that Mayon is still inflated, especially on the northwest and southeast.

Alert Level 3 is maintained over Mayon Volcano, which means that it is currently in a relatively high level of unrest as magma is at the crater and hazardous eruption within weeks or even days is possible. It is therefore recommended that the 6-km radius Permanent Danger Zone (PDZ) be evacuated due to the danger of PDCs, lava flows, rockfalls and other volcanic hazards. Increased vigilance against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice is also advised. Heavy rainfall could generate channel-confined lahars and sediment-laden streamflows in channels where PDC deposits were emplaced. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft. Based on the current prevailing wind pattern, ash fall events may most likely occur on the south side of the volcano. DOST-PHIVOLCS maintains close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders.