During 13-19 PHIVOLCS reported growth of the new summit dome, slight ground deformation, and increased volcanic gas emission at Mayon. On 16-17 August a few rockfalls and one earthquake were detected. On 16-18 August moderate emission of white steam plumes drifted SE, SW, NNE and NE. PHIVOLCS had raised the Alert Level to 2 (on a scale of 0-5) on 15 August.

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)