Mayon Volcano remained under Alert Level 3 as of Thursday morning, indicating high levels of unrest, with ongoing lava flows and frequent volcanic activity recorded over the past 24 hours, state volcanologists said.

In its 5 a.m. advisory on April 16, the Philippine Institute of Volcanology and Seismology reported continued lava effusion from the summit crater. Lava flows were observed advancing through multiple gullies, reaching approximately 3.8 kilometers in Basud, 3.2 kilometers in Bonga, and 1.3 kilometers in Mi-isi.

The agency also noted intermittent weak strombolian eruptions and short-lived lava fountaining events, indicating sustained magmatic activity beneath the volcano.

A total of 66 volcanic earthquakes were recorded, including 17 volcanic tremors lasting between one and 27 minutes. In addition, monitoring instruments detected 304 rockfall events and five pyroclastic density current signals, or ash-laden flows, descending the slopes.

Sulfur dioxide emissions averaged 1,676 tons per day on April 15, while moderate steam-laden plumes rose up to 500 meters above the crater before drifting southwest.

Ground deformation data showed short-term deflation of the edifice, although slight inflation was observed on the northeastern flank, suggesting ongoing subsurface processes.

PHIVOLCS said Alert Level 3 means that magma is at the crater and hazardous eruption remains possible, urging the public to remain vigilant and avoid the six-kilometer permanent danger zone around the volcano.