Report on Mayon (Philippines) — 22 August-28 August 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 August-28 August 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Mayon (Philippines). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 22 August-28 August 2001. Smithsonian Institution and US Geological Survey.
13.257°N, 123.685°E; summit elev. 2462 m
All times are local (unless otherwise noted)
Volcanic activity remained low at Mayon during 22-28 August. There was relatively little seismic activity, slight inflation, occasional observations of incandescence at the summit, and a moderate amount of steam emitted from the volcano. SO2 emission rates remained well above the baseline value of 500 metric tons per day. PHIVOLCS reminded residents along the banks of major channels that lahars and torrential stream flows during heavy rains could remobilize material from pyroclastic-flow deposits. The volcano remained at Alert Level 3.
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.