Increased seismic activity and lava flows observed at Mayon volcano, Philippines

The Philippine Institute of Volcanology and Seismology reported a significant rise in both seismic activity and lava effusion at Mayon Volcano on October 21, 2023.

Mayon Volcano, one of the most active volcanoes in the Philippines, experienced an increase in both seismic activities and lava effusion, according to a report by the Philippine Institute of Volcanology and Seismology (Phivolcs) on October 22, 2023. Within a 24-hour period ending at 00:00 UTC, the Mayon Volcano Network recorded 70 volcanic earthquakes, including 65 tremor events with durations ranging from 2 minutes to 4 hours and 31 minutes. Additionally, the network observed one pyroclastic density current event and 51 rockfall events.

The lava flows advanced to approximately 3.4 km (2.11 miles) in Bonga Gullies, 2.8 km (1.74 miles) in Mi-isi Gullies, and 1.1 km (0.68 miles) in Basud Gullies. Debris from rockfalls and pyroclastic density currents generated by the collapse of the summit dome were deposited within a 4 km (2.49 miles) radius of the crater.

“LOOK! A phase of increased lava effusion at Mayon began at 10:10 PM of 21 October 2023 with an abrupt intensification of incandescence at the summit crater followed by lava flow and rockfall at the Miisi and Bonga Gullies,” PHIVOLCS volcanologists noted.

The videos below were captured by the IR cameras at Mayon Volcano Observatory (south) and Mayon Resthouse (north):

The levels of sulfur dioxide (SO₂) emissions averaged 727 tonnes per day as of October 21, 2023. Monitoring data indicated inflation of the northwestern upper and middle slopes since late July 2023 and October 2023, respectively. Long-term ground deformation parameters showed that Mayon is still generally inflated relative to baseline levels.

The Alert Level for Mayon volcano remains at 3, indicating a high level of unrest and the possibility of a hazardous eruption within weeks or even days. A 6 km (3.7 miles) radius Permanent Danger Zone (PDZ) is advised to remain evacuated due to various volcanic hazards, including pyroclastic density currents, lava flows, and rockfalls. Additional vigilance against pyroclastic density currents, lahars, and sediment-laden streamflows along channels draining the edifice is also recommended.

Civil aviation authorities are advised against flying close to the volcano’s summit as ash from any sudden eruption could be hazardous to aircraft. Based on current wind patterns, ashfall events are most likely to occur on the south side of the volcano.

References:

¹ MAYON VOLCANO BULLETIN – PHIVOLCS – 22 October 2023 8:00 AM

Featured image credit: PHIVOLCS