Report on Mayon (Philippines) — 31 January-6 February 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 January-6 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, 31 January-6 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)
PHIVOLCS reported that numerous shallow earthquakes, high SO2 emission rates, and sustained inflation during the week reflected the active state of the growing summit lava dome. They reported that during the week up to 46 volcanic earthquakes were recorded per day, the SO2 emission rate increased from 2,600 metric tons per day (t/d) on 1 February to 5,330 t/d on 5 February, and electronic tiltmeters on the N flank of the cone continued to detect inflation at the volcano's edifice. Incandescence was visible periodically at the summit. On 1 February, officials recommended that residents of the five towns within the 6-km-radius Permanent Danger Zone evacuate the area. In addition, PHIVOLCS warned residents just outside of the Permanent Danger Zone to be alert for potential hazardous volcanic flows, which may be channeled by rivers and gullies that radiate from the summit. 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.