Increased Seismic Activity Detected at Kanlaon Volcano

The Philippine Institute of Volcanology and Seismology (Phivolcs) reported a surge in seismic activity at Kanlaon Volcano early Thursday, recording 64 volcano-tectonic (VT) earthquakes.

The uptick signals “progressive rock-fracturing beneath the volcano as rising magma drives a path towards the surface,” according to Phivolcs.

Current sulfur dioxide (SO₂) emissions from Kanlaon have increased to an average of 7,087 tons per day, compared to 4,234 tons per day prior to the volcano’s June eruption.

The rise in emissions and seismic activity has prompted Phivolcs to maintain Kanlaon’s status at Alert Level 2, indicating ongoing volcanic unrest.

Phivolcs warned that further developments in seismic activity could lead to increased eruptive unrest and possibly elevate the alert level.

If the volcano’s alert level reaches Level 3, it would indicate magma nearing the surface, increasing the likelihood of a hazardous eruption within weeks.

As a precaution, Phivolcs has strictly prohibited residents from entering the 4-kilometer-radius Permanent Danger Zone around the volcano.

The most recent eruption of Kanlaon occurred in early 2024, producing ash plumes that reached over 500 meters above the crater and resulting in ashfall in surrounding areas.

Though brief, this eruption affected nearby residents, prompting the reinforcement of the Permanent Danger Zone (PDZ) and temporary evacuation measures for communities close to the volcano.

Kanlaon, which straddles Negros Occidental and Negros Oriental, has had a history of eruptions. In 2006, a phreatic explosion caused ashfall in neighboring towns, while a 2017 eruption emitted ash plumes up to 1.5 kilometers high, triggering safety protocols in the surrounding 4-kilometer danger zone.

Currently, Phivolcs has prohibited residents from entering the 4-kilometer PDZ due to potential hazards from sudden eruptions and pyroclastic flows.

If the alert level reaches 3, Phivolcs warns of “explosive volcanic eruptions,” advising local governments to prepare for emergency responses, including possible evacuations.