The slow effusion of lava from the crater of Mayon Volcano has continued despite fewer earthquakes in the previous 24 hours, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Tuesday, July 25.
In the past 24 hours, Phivolcs had recorded 32 low-frequency volcanic quakes (LFVQs), down from 184 LFVQs in the previous monitoring.
However, it noted that the slow effusion of lava from the summit crater of Mayon Volcano continued to feed and bulk up established lava flows on the Mi-isi, Basud, and Bonga gullies on the southern, eastern, and southeastern flanks of the volcano.
Lava flows on the Mi-isi, Basud, and Bonga gullies have maintained distal lengths of approximately 2.8 kilometers (km), 600 meters, and 2.8 km respectively.
Phivolcs said debris was still deposited within four kilometers of the crater from rockfall and pyroclastic density currents (PDCs) caused by the collapses of the lava flow margins and the summit dome.
In the past 24 hours, Mayon Volcano had four PDCs and 138 rockfall occurrences.
(Left) The Tropospheric Monitoring Instrument on board the ESA Copernicus Sentinel-5 satellite detected a significant sulfur dioxide plume from Mayon Volcano on June 28, 2023. (Right) An intense emissivity of a superheated degassing plume from Mayon crater as recorded by the Bical, Sto. Domingo Station. (Phivolcs)
Heightened unrest persists
Given these observations, Phivolcs said Mayon Volcano remains on Alert Level 3, which means it is still in a relatively high level of unrest and that a potentially hazardous eruption may occur within weeks or even days.
Communities near the restive volcano are recommended 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.