Report on Mayon (Philippines) — 10 September-16 September 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 September-16 September 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Mayon (Philippines). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 September-16 September 2014. 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 Mayon’s earthquakes, rockfall events, and an inflationary trend from leveling surveys on 15 September. A noticeable escalation occurred later that day, including 39 rockfall events and 32 low-frequency volcanic earthquakes. Crater glow became visible around 2000 and PHIVOLCS released an informational bulletin at 2200 announcing Alert Level 3. On 16 September incandescent rockfalls spread to the upper reaches of Bonga Gully on the SE flank.
News reports highlighted the evacuation orders announced by the governor of Albay province, which included the 6 km permanent danger zone surrounding the volcano; an assisted evacuation was enforced for the 6-8 km extended danger zone. In an interview with the press, the governor noted that some residents had already fled their homes in Guinobatan (11.8 km SW) on the evening of 15 September.
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.