Report on Mayon (Philippines) — 20 August-26 August 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 August-26 August 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, 20 August-26 August 2014. Smithsonian Institution and US Geological Survey.
13.257°N, 123.685°E; summit elev. 2462 m
All times are local (unless otherwise noted)
During 20-26 August PHIVOLCS reported no incandescence at Mayon, despite the emergence of a summit dome, slight ground deformation, and increased volcanic gas emission. On most days seismic instruments recorded a few rock falls and sparse earthquakes. During 20-25 August observers noted moderate emission of white steam plumes that drifted SW, WSW, NE, ENE, and SSW. The Alert Level remained at 2 (on a scale of 0-5).
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.