Mayon spews ash, triggers more volcanic quakes
Published Jul 19, 2023 04:45 am
Mayon Volcano continued to exhibit signs of escalating unrest as indicated by ash emissions, volcanic earthquakes, and rumbling sounds over the past 24 hours, said the Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday, July 19.
Phivolcs detected 304 weak and shallow low-frequency volcanic earthquakes (LFVQs) associated with discrete and rapid volcanic gas releases from Mayon’s crater.
“Some of these degassing events were accompanied by audible thunder-like sounds and entrained ash at the crater to produce ‘ashing’ of short dark plumes,” it said.
Phivolcs’ seismic, infrasound, visual, and thermal monitors recorded 30 ashing events between 5:33 p.m. on July 18 and 4:34 a.m. on July 19, each lasting 20 to 40 seconds and ejecting a plume that drifted southwest at a height of 150 to 300 meters.
Moreover, the slow lava effusion continues to feed and bulk up lava flows on Mi-isi, Bonga, and Basud gullies on Mayon Volcano's southern, southeastern, and eastern flanks, maintaining distal lengths of 2.8 kilometers, 2.4 kilometers, and 600 meters from the crater, respectively.
Phivolcs said rockfall and pyroclastic density currents (PDCs) caused by the collapse of the summit dome and the lava flow margins left debris four kilometers from the crater.
In the past 24 hours, 137 rockfall occurrences and three PDCs were recorded by the Mayon Volcano Network.
However, Phivolcs pointed out that the combined seismic energy release from volcanic earthquakes, rockfalls, and PDCs has not gone above the trend of effusive activity.
Mayon Volcano ejects massive pyroclastic density currents (PDC) toward the Basud Gully in Sto. Domingo town in Albay province around 5:30 p.m. on July 10, 2023. (Niño Luces/Manila Bulletin)
Mayon Volcano ejects massive pyroclastic density currents (PDC) toward the Basud Gully in Sto. Domingo town in Albay province around 5:30 p.m. on July 10, 2023. (Niño Luces/Manila Bulletin)
Alert level 3 maintained
According to Phivolcs, Mayon Volcano is still at alert level 3, indicating that it is still in a relatively high level of unrest and that a potentially hazardous eruption may occur within weeks or even days. Phivolcs advised communities near the restive volcano to maintain increased vigilance against lahars and sediment-laden stream flows along channels draining the volcano edifice, as heavy rainfall could cause channel-confined lahars and sediment-laden stream flows. Since Mayon Volcano’s status was upgraded twice in the past month, first to level 2 on June 5 and then to level 3 on June 8, Phivolcs strongly advised that entry into the six-kilometer permanent danger zone be strictly prohibited. Furthermore, it warned that ash fall may occur in areas south of Mayon Volcano due to current wind patterns. Phivolcs advised pilots to avoid flying near the volcano's summit because ash from a sudden eruption can be dangerous to aircraft.