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Report on Mayon (Philippines) — 1 August-7 August 2001


Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
1 August-7 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, 1 August-7 August 2001. Smithsonian Institution and US Geological Survey.

Weekly Report (1 August-7 August 2001)



13.257°N, 123.685°E; summit elev. 2462 m

All times are local (unless otherwise noted)

Volcanic activity during 1-4 August at Mayon consisted of high SO2 emission, high- and low-frequency harmonic tremor and low-frequency volcanic earthquakes, slight inflation of the edifice, and the ejection of lava fragments up to 100 m above the crater rim. PHIVOLCS stated that activity had decreased since the 26 July eruptions and the volcano was in a mild state of eruption. According to news reports, approximately 26,500 people were still evacuated from their homes near the volcano. Mayon remained at Alert level 5, the highest level.

Geological Summary. Symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the most active volcano of the Philippines. The steep upper slopes are capped by a small summit crater. Recorded eruptions since 1616 CE 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 damaged populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Manila Bulletin, Associated Press