Report on Mayon (Philippines) — 12 December-18 December 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 December-18 December 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Mayon (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 December-18 December 2012. 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 since the Alert Level for Mayon was lowered to 1 on 2 March, seismicity decreased, and ground and tilt monitoring data suggested regional faulting and not magmatic intrusion. Steaming from the crater was diffuse and crater incandescence had ceased in March. Sulfur dioxide emissions had decreased to below baseline levels. On 27 November the Alert Level was lowered to 0 and the public was reminded not to enter the 6-km-radius Permanent Danger Zone (PDZ).
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.