The solidification of magma inside Kanlaon Volcano near the crater traps the gas, as characterized by weak sulfur dioxide (SO2) emission and degassing, which could lead to the blockage of the volcanic conduit, the passageway for gas and magma leading to the crater.

The blockage could lead to pressure build-up within the volcanic conduit or channel, which could trigger minor eruptions within the summit crater of Kanlaon similar to the event on February 6, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

Prior to the February 6 event, which lasted for two minutes, the SO2 flux was recorded at an average of 2,249 tons per day, which is significantly lower than the medium-term average of 4,484 tons per day monitored since June 3, 2024.

In a statement, Phivolcs said that Kanlaon Volcano’s degassing has been weak since the evening of February 5, while the upper to middle slopes have been swelling since January 10.

Volcanic ash generated from this event, in addition to ash deposits around Kanlaon from its previous activities, prompted mudflows along Buhangin River which goes through La Castellana and Moises Padilla towns.

The explosion also generated an airwave and was heard as a booming sound in Barangay Yubo, La Carlota City and Barangay Sag-ang, La Castellana.

Following the minor explosive eruption, the La Castellana Incident Management Team immediately convened to discuss additional precautionary measures and distributed supplemental face masks to their residents.

Meanwhile, last February 15, an ash emission from the summit crater of Kanlaon was recorded which lasted about eight minutes, with a grayish plume that rose 1,500 meters above the summit crater, as per Phivolcs record.

Ashfall was reported in Barangays Abuanan, Binubuhan, Dulao, Ilijan, Ma-ao, and Mailum in Bago City, Negros Occidental.

Alert Level 3 remains over Kanlaon Volcano, indicative of possible short-lived explosions in the short term which may cause pyroclastic density currents within the six-kilometer extended danger zone.

Phivolcs recommends keeping residents evacuated from within the six-kilometer radius due to the threats of lava flows, rockfall, and lahar and sediment-laden stream flows should heavy rains occur during an eruptive unrest.

Local governments and communities are also advised to always be prepared for the potential escalation of Kanlaon Volcano’s unrest. (PIA-Negros Occidental)