Report on Mayon (Philippines) — 29 October-4 November 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 October-4 November 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Mayon (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 October-4 November 2014. Smithsonian Institution and US Geological Survey.
13.257°N, 123.685°E; summit elev. 2462 m
All times are local (unless otherwise noted)
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).
Geologic Background. Beautifully symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the Philippines' most active volcano. The structurally simple edifice has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions date back to 1616 and 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 devastated populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.