DSWD DROMIC Report #64 Mayon Volcanic Activity 16 August 2023, 6PM – Philippines

At 8 a.m. on 16 August 2023, Alert Level 3 is maintained over Mayon Volcano, meaning that it is currently at a relatively high level of unrest and a potentially fatal eruption is possible within weeks or even days.

During the past 24 hours, slow lava flows from Mayon Volcano’s summit crater continued to feed established lava flows in the Bonga (southeast), Mi-ic (south) and Pasut (east) valleys. Lava flows have sustained their respective advances approximately 3.4 kilometers, 2.8 kilometers, and 1.1 kilometers from the crater. Rocks formed by the slopes of the lava flow rims and the collapse of the peak’s dome are still accumulated in the crater within four (4) kilometers. The Mayon volcanic network recorded a total of one hundred seventy-five (175) volcanic earthquakes, of which ninety-six (96) tremor events lasted between one (1) and twenty-one (21) minutes. Some of these tremors were accompanied by rumbling sounds that could be heard within a 7-km radius of Mayon Crater. Additionally, the network detected sixty (60) rockfall events and six (6) PDCs. Volcanic sulfur dioxide (SO2) emissions on 15 August 2023 averaged 1,113 tonnes/day. Short-term observations from electronic gradient and GPS tracking indicate inflation of the middle flanks from the third week of July 2023. Long-term ground deformation parameters leveling from EDM, continuous GPS and electronic tilt monitoring indicate that Mayon is still generally elevated compared to baseline levels.

A 6-km perimeter Permanent Danger Zone (PDZ) is therefore recommended to be evacuated due to the risk of PDCs, lava flows, rockfalls and other volcanic hazards. Extra vigilance is advised against pyroclastic density currents, lahars and alluvial flows. Heavy rainfall can produce channel-controlled lahars and sediment-rich streams in channels with PDC deposits.

Civil aviation authorities have advised pilots to avoid flying near the volcano’s summit, as sudden eruptions of ash can be dangerous for aircraft. Based on the prevailing winds, ash fall events are most likely to occur on the south side of the volcano. DOST-PHIVOLCS is closely monitoring Mayon Volcano and any new development will be communicated to all concerned stakeholders.