Report on Mayon (Philippines) — 7 February-13 February 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 February-13 February 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Mayon (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 February-13 February 2018. 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 7-13 February activity at Mayon continued to be characterized daily by lava effusion from the summit crater, rockfalls, lava fountains, steam emissions, advancing lava flows on the flanks, and pyroclastic flows. Numerous rockfall events were generated from the front and margins of advancing lava flows. Lava fountaining was nearly continuous during 6-10 February, with around 290 lava-fountaining events recorded by the seismic network from 0557 on 5 February until around 0700 on 10 February. The events each lasted between 3 and 233 minutes, and were accompanied by rumbling sounds audible with a 10-km radius. Lava fountaining was sporadic during 11-13 February. Lava fountains during phases of both nearly continuous and sporadic activity rose as tall as 400 m, and produced steam plumes up to 2.5 km above the crater that drifted in multiple directions. Lava flows advanced to 3.3 km, 4.5 km, and 900 m in the Mi-isi (S), Bonga (SE), and Basud (E) drainages, respectively. Pyroclastic density currents traveled 4.2-4.6 km in the Mi-isi, Bonga, and Basud drainages. The Alert Level remained at 4 (on a 0-5 scale) and the public was warned to remain outside of the Danger Zone defined as an area within an 8-km radius.
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.