Report on Mayon (Philippines) — 24 August-30 August 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 August-30 August 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Mayon (Philippines). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 24 August-30 August 2005. 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 on 23 August that an aerial survey of Mayon conducted on 17 August revealed that lava had accumulated within the volcano's summit crater. The lava dome was extruding very slowly and the volume of lava was contained within the crater. PHIVOLCS warned that the volcano remains at Alert Level 2, and that people cannot enter the Permanent Danger Zone of 6 km radius around the volcano.
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.