The Philippine Institute of Volcanology and Seismology (PHIVOLCS) recorded 55 volcanic earthquakes, and 347 rockfall events at Mayon Volcano on Friday, May 22.

In its 24-hour observation bulletin released Friday, PHIVOLCS also reported 17 volcanic tremors, two pyroclastic density current (PDC) signals, continued lava effusion, and sustained lava flows across multiple gullies of the volcano.

Lava was observed flowing down the Basud Gully (3.8 km), Bonga Gully (3.2 km), and Mi-isi Gully (1.7 km), accompanied by weak Strombolian activity at the summit crater. The eruption has now been ongoing for 136 consecutive days.

Sulfur dioxide (SO2) emissions were measured at 2,284 tonnes per day on May 21, indicating persistent degassing from the volcano. A plume rising approximately 800 meters from the crater was also observed, drifting toward the west, west-northwest, and southwest directions.

Ground deformation data showed short-term inflation and deflation patterns, with localized swelling detected in the northeastern flank of the volcano.

PHIVOLCS further confirmed that volcanic tremors lasted between 2 to 20 minutes each, while rockfall and collapse-related activity continued to generate incandescent materials and PDCs, locally known as “uson.”

On May 21, time-lapse footage captured minor Strombolian activity at the summit crater at 8:41 p.m. and 9:58 p.m., as well as lava effusion and collapse-fed pyroclastic density currents in the Bonga Gully at around 9:48 p.m.

Authorities maintained Alert Level 3 over Mayon Volcano, warning of continued hazardous activity.

Entry into the 6-kilometer Permanent Danger Zone remains strictly prohibited due to the risk of sudden explosive eruptions, lava flows, rockfalls, and pyroclastic density currents.