Mayon’s activity in the past 24 hours was characterized by sporadic and weak lava fountaining, lava flow and degassing from the summit crater. Three (3) discrete lava fountaining episodes were recorded at 1:03 AM and 4:49 PM yesterday and 1:59 AM this morning. The first of these lasted twelve hours and eighteen minutes, generating grayish ash plumes that rose 400 m above the summit crater. Discrete seismic events associated with otherwise obscured lava fountaining lasted three to 21 minutes and were recorded until 1:21 PM yesterday. The second episode lasted 43 minutes and consisted of discrete seismic events of up to 10 minutes duration that were accompanied by rumbling sounds audible beyond 10 kilometers of the summit crater. The third episode started early this morning and is characterized by discrete signals with attendant incandescent lava flow. Lava flows have advanced to 3.3 kilometers, 4.5 kilometers and 900 meters down the Miisi, Bonga and Basud Gullies, respectively, from the summit crater. Pyroclastic density currents or PDCs have deposited to the 4.6, 4.5 and 4.2 kilometer reaches of the Miisi, Bonga and Basud Gullies, respectively.
A total of fifty-five (55) volcanic earthquakes, most of which corresponded to lava fountaining events, and three (3) rockfall events were recorded by Mayon's seismic monitoring network. Sulfur dioxide (SO2) emission averaged 1,339 tonnes/day on 17 February 2018. Electronic tilt and continuous GPS still record sustained swelling or inflation of the edifice since November and October 2017, consistent with pressurization by magmatic intrusion.
Alert Level 4 remains 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. 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. DOST-PHIVOLCS maintains close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders.
