The Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday, July 12, continued to record rockfalls and volcanic earthquakes due to the ongoing effusive eruption of Mayon Volcano in Albay.
Phivolcs said Mayon Volcano had 423 rockfall events, 24 volcanic earthquakes, as well as eight dome and lava front collapse-triggered pyroclastic density currents (PDCs) between 5 a.m. on Tuesday, July 11, and 5 a.m. on Wednesday, July 12.
The “very slow” effusion of lava from Mayon Volcano’s crater has persistently fed lava flows and collapsed debris on the Mi-isi and Bonga gullies on the southern and southeastern sides of the volcano.
Rockfalls and PDCs were also observed along these gullies, as well as on the Basud gully on the eastern flank of Mayon.
The approximate lengths of lava flow stayed at 2.8 kilometers (km) and 1.3 km, respectively, along the Mi-isi and Bonga gullies, while collapsed debris was still deposited 4 km along the Basud gully.
The Mayon Volcano also continued to emit “moderate” amounts of sulfur dioxide, producing a 750-meter-high steam plume that drifted west-southwest.
The Mayon Volcano ejects massive pyroclastic density currents (PDC) towards 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 still up
As of Wednesday, Mayon Volcano is still in a relatively high level of unrest and that a potentially hazardous eruption within weeks or even days is still be possible.
Phivolcs said Mayon Volcano remains under Alert Level 3.
Communities near the restive volcano were advised 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.
It was strongly advised that entry into the six-kilometer permanent danger zone be strictly prohibited.
Phivolcs also noted that ash fall is most likely to occur in areas south of Mayon Volcano due to current wind patterns.
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 due to “intensified magmatic unrest.”