Report on Mayon (Philippines) — 29 May-4 June 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 May-4 June 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Mayon (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 May-4 June 2013. 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 30-31 May diffuse, short-lived, bluish, hydrogen sulfide emissions rose from Mayon, and incandescence from the crater was observed. Sulfur dioxide emissions fluctuated between 5 and 388 tonnes per day, remaining below the normal level of 500 tonnes per day. Seismicity was low, while a recently concluded ground deformation survey indicated slight inflation compared to February survey data. Based on the visual observations, and despite that most monitoring parameters remained within baseline levels, PHIVOLCS raised the Alert Level to 1 and reminded the public 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.