Report on Mayon (Philippines) — 7 February-13 February 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 February-13 February 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, 7 February-13 February 2001. Smithsonian Institution and US Geological Survey.
13.257°N, 123.685°E; summit elev. 2462 m
All times are local (unless otherwise noted)
The PHIVOLCS reported that volcanic activity remained high at Mayon. Abundant low-frequency volcanic earthquakes associated with dome growth took place on 7, 8, 9, 11, and 12 February and consisted of 29, 30, 29, 45, and 30 events, respectively. Also on 12 February seismometers detected 2 rockfalls. The crater emitted voluminous steam and sulfur, with a maximum of ~7,100 metric tons of SO2 detected on 12 February. Tiltmeters on the volcano's N flank continued to detect slight edifice inflation. On 11 February, PHIVOLCS reported that most of the springs in the E and S quadrants of the volcano showed a decrease in discharge, despite increasing rainfall. Inclement weather prevented observations of the volcano. Mayon remained at Alert Level 3 (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.