PHIVOLCS reported that during 21-27 February activity at Mayon continued to be characterized by daily lava effusion from the summit crater, lava fountains on most days, steam-and-ash emissions, advancing lava flows on the flanks, and pyroclastic flows. Weak and sporadic lava fountaining events each lasted between 2 and 77 minutes, and were sometimes accompanied by rumbling sounds audible within a 10-km radius. Each day there were 1-21 pyroclastic flows generated by lava-collapse events traveling as far as 5 km down the Mi-isi, Bonga-Buyuan, 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.

Geological Summary. Symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the most active volcano of the Philippines. The steep upper slopes are capped by a small summit crater. Recorded eruptions since 1616 CE range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often damaged populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)