|PUBLIC ADVISORY: Notice of raising Mayon Volcano’s status from Alert Level 3 to Alert Level 4 as of January 22, 2018.|
PHIVOLCS: MAYON VOLCANO BULLETIN 26 February 2018 8:00 A.M.
PHIVOLCS has raised the alert level to Alert Level 4 in effect over Mayon Volcano. The public is strongly advised to be vigilant and desist from entering the eight (8) kilometer-radius danger zone, and to be additionally vigilant against pyroclastic density currents, lahars and sediment-laden stream flows along channels draining the edifice.
SUMMARY | Alert Level 4 remains in effect over Mayon Volcano.
Mayon’s condition for the past 24 hours was characterized by weak lava fountaining, lava effusion and degassing from the summit crater. As of 7:04 AM this morning, a total of thirty six (36) discrete episodes of lava fountaining lasting two (2) to nineteen (19) minutes have occurred, accompanied by booming and rumbling sounds audible beyond 10 kilometers of the summit crater. Lava fountains 50-200 meters tall generated steam-laden plumes that rose to 150-600 meters from the summit before drifting southwest, west-northwest, northwest, and northeast. In the evening, lava effusion from the vent was observed to continue feeding lava flows that have maintained fronts at 3.3 kilometers, 4.5 kilometers and 900 meters on the Miisi, Bonga and Basud Gullies, respectively, from the summit crater. Only two (2) episodes of lava-collapse pyroclastic density currents (PDC) were visually observed between 10:33 AM and 10:38 AM yesterday on the Miisi, Basud and Bonga-Buyuan Gullies within 4 kilometers of the summit crater.
A total of one hundred twenty-four (124) volcanic earthquakes and one (1) rockfall event were recorded by Mayon's seismic monitoring network. Sulfur dioxide (SO2) emission was measured at an average of 2070 tonnes/day on 23 February 2018. Deflation of the lower slopes that began on 20 February was recorded by electronic tilt, consistent with the transition to quiet lava effusion at the summit crater, a brief lull and resumption of sporadic fountaining. Nonetheless, overall electronic tilt and continuous GPS data indicate that the edifice is still swollen or inflated relative to November and October 2017, consistent with campaign Precise Leveling data acquired this week.