Lava flow activity has commenced from the summit crater of Mayon Volcano, the Philippine Institute of Volcanology and Seismology announced on Monday, June 12.
Mayon Volcano spews ash and lava as seen from Legaspi city, Albay, on June 11, 2023. The province of Albay was placed under a state of calamity due to the threat of an eruption of Mayon Volcano. The office of Civil Defense had evacuated 2,638 families in the towns of Camalig, Ligao City, Daraga, Guinobatan, Malilipot and Tabaco City. (Ali Vicoy)
In its latest bulletin, Phivolcs said that this development was accompanied by only weak seismic activity and a slight swelling of the upper portions of the edifice prior to lava flow based on electronic tilt data.
"The activity formed two lobes of lava that emplaced within 500 meters from the crater and shed lava debris on the south and southeastern, and eastern gullies that fell within 2 kilometers from the crater," the agency explained.
Within the past 24-hour period, the Mayon Volcano Network recorded 21 weak volcanic earthquakes and 260 rockfall events.
Phivolcs said that three dome-collapse pyroclastic density currents (PDC) that lasted two to four minutes were also detected. Sulfur dioxide emission averaged 642 tonnes/day on Sunday, June 11.
"Short-term observations from EDM and electronic tiltmeter monitoring show the upper slopes to be inflating since February 2023," the agency said.
"Longer-term ground deformation parameters based on EDM, precise leveling, continuous GPS, and electronic tilt monitoring indicate that Mayon is still inflated, especially on the northwest and southeast," it added.
Alert Level 3 remains hoisted over Mayon Volcano, which means that it is currently in a relatively high level of unrest as magma is at the crater and hazardous eruption is possible within weeks or even days.
Phivolcs recommended that the 6-km radius Permanent Danger Zone (PDZ) be evacuated due to the danger of PDCs, lava flows, rockfalls and other volcanic hazards.