A minor explosive eruption occurred at the summit crater of Kanlaon Volcano on Negros Island at 3:11 p.m. yesterday, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).
The eruption lasted two minutes based on seismic and infrasound records from the Kanlaon Volcano Network.
The eruption generated a poorly visible plume that rose 600 meters above the vent before drifting southwest, scattering thin ashfall over Santa Mercedes and San Luis, Barangay Sag-ang, La Castellana town in Negros Occidental.
The explosion also generated an airwave that was recorded at 70 Pascals five kilometers east of the summit crater and heard as a booming sound in Barangay Yubo, La Carlota City and Barangay Sag-ang, La Castellana.
Sulfurous fumes were also reported in several barangays of La Castellana.
As the eruption occurred during rainy weather, Phivolcs added, “syneruption channel-confined lahars were immediately generated in the Buhangin River which flow through La Castellana and Moises Padilla, Negros Occidental.”
“Prior to the event, sulfur dioxide flux was measured at an average of 2,249 tons per day, a significant drop from the medium-term average of 4,484 tons per day since June 3, 2024, while degassing from the summit crater has been weak since the previous evening.
“The upper to middle slopes of the edifice have been undergoing inflation or swelling since January 10, 2025, and when occasional plugging of the volcanic conduit occurs and sulfur dioxide emission and degassing weakens, the resulting pressure build-up within the conduit could trigger explosions,” Phivolcs further said.
Alert Level 3 or magmatic unrest prevails over Kanlaon Volcano.
“This means that the magmatic eruption that occurred may be followed by similar short-lived explosive eruptions in the short term which may generate pyroclastic density currents [PDC] within the six-kilometer radius area on the summit,” Phivolcs also said.
It has been recommended that communities within a six-kilometer radius of the summit crater be evacuated due to the danger of lava flows, rockfalls, pyroclastic density currents or PDCs and other related hazards.
Local government units must also prepare their communities within the PDC hazard zone for subsequent evacuation in case unrest further escalates and a hazardous worst-case explosive eruption becomes imminent.
Increased vigilance against potential syneruption lahars and sediment-laden streamflows in channels draining the edifice is strongly advised should intense rains occur during eruptive unrest.
Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft. (GMA Regional TV)