Lava effusion with lava flow from Mayon Volcano were observed over the past 24 hours, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported on Tuesday.

Based on its 24-hour monitoring from 12 a.m. to 12 a.m., Phivolcs recorded lava flowing through several gullies: up to 3.8 kilometers in Basud, 2.2 kilometers in Bonga, and 1.3 kilometers in Mi-isi.

The volcano also recorded four volcanic earthquakes, 305 rockfall events, and 20 pyroclastic density currents or ash flows during the monitoring period.

Phivolcs said a crater glow was visible, indicating ongoing lava at the summit. However, the volcano was mostly obscured by clouds. Ground deformation data further showed that the edifice remains inflated, suggesting that magma is still present beneath the volcano.

Mayon emitted 3,981 tonnes of sulfur dioxide per day on Monday, February 23.

Alert Level 3 remains in effect over Mayon Volcano, signaling heightened volcanic unrest and the possibility of hazardous eruptions.

The agency also said entry into the six-kilometer Permanent Danger Zone (PDZ) is strictly prohibited, and flying any aircraft close to the volcano is not allowed.

Phivolcs warned that hazards such as rockfalls, lava flow, pyroclastic density currents, ashfall, and lahars during heavy rainfall may occur.