The lava flow from Mayon Volcano continued to cascade down its slopes at a “very slow” rate and has now reached a length of up to 2.7 kilometers as of Sunday, July 2, said the Philippine Institute and Volcanology and Seismology (Phivolcs).
From 5 a.m. on Saturday, July 1, to 5 a.m. on Sunday, July 2, Phivolcs said the very slow effusion of lava from the summit crater of Mayon Volcano continued to feed lava flows and collapse debris on the Mi-isi and Bonga gullies on the southern and southeastern flanks, respectively.
Lava flows measuring approximately 2,700 and 1,300 meters have descended to the Mi-isi and Bonga gullies, respectively.
Phivolcs said rockfall and pyroclastic density current (PDC) occurrences were also observed at the Mi-isi, Bonga, and Basud gullies.
Basud Gully is on the eastern portion of Mayon Volcano.
Phivolcs said volcanic debris has descended 4,000 meters from the crater.
The “very slow” lava effusion from Mayon Volcano's summit crater continues on June 26, 2023, causing incandescent rockfall and pyroclastic density current (PDC) activity along the Mi-isi and Bonga Gullies. (Screengrab from Phivolcs)
2 PDCs, 397 rockfalls, 4 volcanic quakes
During the 24-hour monitoring of the Mayon Volcano, Phivolcs also recorded two lava dome collapse-triggered PDCs that lasted two minutes, 397 rockfall events, and four volcanic earthquakes.
A significant amount of gas was also constantly released from Mayon, which caused its emission of steam-laden plumes about 1,500 meters high before dissipating to the southwest, south-southwest, and northwest.
Phivolcs noted that the concentrations of sulfur dioxide (SO2) averaged 864 tons per day when it was last measured on July 1.
‘Intensified’ unrest persists
Mayon Volcano is still under Alert Level 3 as it is “currently in a relatively high level of unrest as magma is at the crater and hazardous eruption within weeks or even days is possible.”
Phivolcs strongly recommended the evacuation of residents within the six-kilometer permanent danger zone due to the risk of PDCs, lava flows, rockfalls, and other volcanic hazards.
In addition, it advised communities to maintain increased vigilance against PDCs, 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.
Pilots were also asked to avoid flying close to the volcano because ash from a sudden eruption may pose hazards to aircraft.
According to Phivolcs, communities on the southern side of Mayon Volcano may most likely experience ash fall events based on the current wind pattern.