State volcanologists maintained Alert Level 3 for Mayon Volcano on Tuesday as the volcano continued to exhibit high levels of seismic activity, including lava effusion and the emission of toxic gas.

The Philippine Institute of Volcanology and Seismology (Phivolcs) reported that lava is flowing 3.8 kilometers down the Basud gully, 2.2 kilometers down the Bonga gully, and 1.3 kilometers down the Mi-isi gully.

Over a 24-hour observation period, instruments recorded four volcanic earthquakes, 305 rockfall events, and 20 pyroclastic density currents — fast-moving flows of ash and volcanic gas locally known as “uson.”

Monitoring teams also measured a sulfur dioxide flux of 3,891 tons on Monday. Exposure to the gas can cause irritation to the eyes, nose and throat.

Under Alert Level 3, the six-kilometer permanent danger zone remains strictly off-limits to the public.