Report on Mayon (Philippines) — 7 March-13 March 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 March-13 March 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 March-13 March 2001. 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 7 to 13 March, 6-33 low-frequency earthquakes were recorded daily. One SO2 emission measurement was made during the week on 4 March, with a reading of 1,750 metric tons. Like the previous weeks, a slight inflationary trend was detected at the volcano's edifice and weak-to-moderate steaming was occasionally seen. At 1509 on 11 March a brief ash discharge reached a height of 150 m and drifted to the SW. At 1940 the same day faint incandescence was observed at the crater using a telescope; graded as level 1 intensity. 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.