In the past 24-hour period, a 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 as well as rockfall and PDCs on these and the Basud (eastern) Gullies. The lava flows have advanced to approximate lengths of two thousand eight hundred (2800) meters and one thousand three hundred (1300) meters along Mi-isi and Bonga gullies, respectively, from the summit crater while collapse debris has deposited to four thousand (4000) meters from the crater. Seven (7) dome-collapse pyroclastic density currents (PDC) that lasted from one (1) to four (4) minutes, two (2) lava front collapse pyroclastic density currents (PDC) that generated 300 meters high light-brown plume, two hundred forty-three (243) rockfall events, and an ongoing repetitive pulse tremor observed since 3:47 PM (PST) of July 3, 2023, were recorded by the Mayon Volcano Network. Continuous moderate degassing from the summit crater produced steam-laden plumes that rose 500 meters before drifting to the west-southwest and west-northwest. Sulfur dioxide (SO2) emission averaged 1,621 tonnes/day on 05 July 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.
DOST-PHIVOLCS