PHIVOLCS reported that during 3-8 December white plumes were occasionally observed rising from Mayon's crater and drifted WSW, SSW, and NW, sometimes downslope. Inclement weather prevented views of the summit on some days. As many as three volcanic earthquakes were recorded per day. Alert Level remained at 3 (on a 0-5 scale). PHIVOLCS reminded residents of the 6-km-radius Permanent Danger Zone (PDZ) around the volcano and the 7-km Extended Danger Zone (EDZ) on the SE flank.

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 periods of andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic density currents 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)