PHIVOLCS reported that during 28 October-4 November white plumes rose from Mayon's crater and drifted SW, WSW, WNW, and NW, sometimes down the flanks. Weak incandescence from the crater was noted at night on 28 October. A few volcanic earthquakes and rockfall signals were recorded during 29-31 October and 4 November. A 4 November report noted that ground deformation had been detected since the beginning of 2014. Tilt data from the network on the NW flank indicated continuing inflation since August, subsequent to a period of inflation in June and July. The inflation events were thought to correspond to a magma body, approximately 107 cubic meters, slowly intruding at depth. Precise leveling measurements also indicated sustained inflation. The Alert Level remained at 3 (on a 0-5 scale).

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)