PHIVOLCS reported that during 14-20 February daily activity at Mayon continued to be characterized by lava effusion from the summit crater, rockfalls, lava fountains, steam emissions, advancing lava flows on the flanks, and pyroclastic flows.
Weak and sporadic lava fountaining events each lasted between 5 and 239 minutes, and were sometimes accompanied by rumbling sounds audible with a 10-km radius.
Heavy rainfall on 14 February caused lahars in the Anoling drainage, and sediment-laden streams in most channels where pyroclastic flow deposits were emplaced.
During 16-17 February lava fountains were 200-500 m tall and generated steam plumes that drifted SW, WSW, and NW.
A lava-fountaining event that began at 0103 on 17 February lasted for 12 hours and 18 minutes.
Lava flows 3.3 km, 4.5 km, and 900 m long in the Mi-isi (S), Bonga (SE), and Basud (E) drainages, respectively, continued to be active.
Pyroclastic flows traveled 4.2-4.6 km in the Mi-isi, Bonga, and Basud drainages.
The Alert Level remained at 4 (on a 0-5 scale) and the public was warned to remain outside of the Danger Zone, defined as an area within an 8-km radius.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)