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Report on Mayon (Philippines) — 23 August-29 August 2023


Mayon

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 23 August-29 August 2023
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2023. Report on Mayon (Philippines) (Sennert, S, ed.). Weekly Volcanic Activity Report, 23 August-29 August 2023. Smithsonian Institution and US Geological Survey.

Weekly Report (23 August-29 August 2023)

Mayon

Philippines

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

All times are local (unless otherwise noted)


PHIVOLCS reported that the eruption at Mayon continued during 23-29 August, with slow lava effusion from the summit crater feeding flows on the S, SE, and E flanks. The lengths of the lava flow in the Mi-Isi (S), Bonga (SE), and Basud (E) drainages remained at 2.8 km, 3.4 km, and 1.1 km, respectively. Collapses at the lava dome and from the lava flows produced incandescent rockfalls and pyroclastic density currents (PDCs, or pyroclastic flows) that descended the three drainages as far as 4 km. Each day seismic stations recorded 109-186 rockfall events and 1-6 PDC events. There were 2-56 daily volcanic earthquakes; those totals included 1-39 tremor events, each with durations of 1-36 minutes, during 23-27 August. Sulfur dioxide emissions were measured on a few days and averaged between 735 and 1,298 tonnes per day, with the highest value recorded on 26 August. The Alert Level remained at 3 (on a 0-5 scale) and residents were reminded to stay away from the 6-km-radius Permanent Danger Zone (PDZ). PHIVOLCS recommended that civil aviation authorities advise pilots to avoid flying close to the summit.

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 periods of andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic density currents 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.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)