Attachments
I. Situation Overview
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As of 20 July 2023 at 8AM, Alert Level 3 is maintained over Mayon Volcano, which means that it is currently in a relatively high level of unrest and hazardous eruption within weeks or even days could still be possible.
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In the past 24-hour period, slow effusion of lava from the summit crater of Mayon Volcano continued to feed and bulk up established lava flows on the Mi-isi (south), Bonga (southeastern) and Basud (eastern) gullies. Respectively, these lava flows have maintained distal lengths of approximately 2.8 kilometers, 2.4 kilometers and 600 meters from the crater. Rockfall and pyroclastic density currents or PDCs generated by collapses of the lava flow margins as well as of the summit dome deposited debris still within four (4) kilometers of the crater. In total, ninety (90) LFVQs, three (3) PDCs, and one hundred sixty-nine (169) rockfall events, as well as three (3) ashing events were recorded by the Mayon Volcano Network. Volcanic sulfur dioxide (SO2) emission averaged 2,622 tonnes/day yesterday, 19 July 2023. Short-term observations from electronic tilt and GPS monitoring indicate a deflation of the eastern lower flanks in early July 2023 and inflation of the northwest middle flanks in the third week of July 2023. Longer-term ground deformation parameters from EDM, precise leveling, continuous GPS, and electronic tilt monitoring indicate that Mayon is still generally inflated relative to baseline levels.
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It is therefore recommended that the 6-km radius Permanent Danger Zone (PDZ) remain evacuated due to the danger of PDCs, lava flows, rockfalls, and other volcanic hazards.
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Increased vigilance against pyroclastic density currents, lahars, and sedimentladen 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.
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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.
Source: DOST-PHIVOLCS
II. Status of Affected Areas and Population
A total of 9,867 families or 38,375 persons are affected in 26 barangays in Albay (see Table 1).