THE Philippine Institute of Volcanology and Seismology (Phivolcs) urged communities on the southern slopes of Negros Island to remain vigilant amid possible intense rains.
Such rains could erode newly deposited loose ash or pyroclastic material on the upper slopes, generating hot lahars and sediment-laden streamflows that may cause life-threatening injuries, washouts, and burial.
This came after Phivolcs reported a minor explosive eruption at Kanlaon Volcano Friday, October 24, 2025, affecting five local government units in the Negros Island Region (NIR).
Phivolcs said a moderately explosive eruption occurred at the summit crater of Kanlaon Volcano at 8:05 p.m. and lasted three minutes, based on seismic and visual recordings.
The eruption generated a short, dense incandescent plume followed by a billowing plume that rose 2,000 meters above the vent before drifting northwest. Large ballistic fragments were also observed to have been thrown around the crater within a few hundred meters.
Provincial and local authorities reported ashfall in areas of Negros Occidental, including Bago City, particularly Barangays Mailum, Ma-ao, Ilijan, Bacong, and Abuanan; La Carlota City—Barangay Ara-al and Sitio Guintubdan; and Pontevedra—Barangay Zamora.
Sulfurous fumes were also strongly experienced in Barangay Cabagnaan, La Castellana, Negros Occidental, and in Barangays Linothangan, Malaiba, and Pula in Canlaon City, Negros Oriental.
Phivolcs said the eruption generated a shock wave, which was recorded at a maximum of 204 Pascals by an infrasound station five kilometers east of the crater, and was heard as a booming sound within a six-kilometer radius.
Incandescent pyroclastic density currents (PDCs) descended the southern slopes within the jurisdiction of La Castellana, reaching up to a kilometer from the crater based on visual and thermal camera monitoring, it added.
Phivolcs said Kanlaon remains under Alert Level 2, which means this most recent explosive eruption may be followed by further moderate-intensity activity, such as ash emission events or similar short-lived explosive eruptions.
Such eruptions could produce dangerous volcanic hazards within the four-kilometer radius Permanent Danger Zone (PDZ), disperse ash to the general west of the volcano, and produce material that could feed lahars in affected drainage channels.
Phivolcs also recommended that communities within the PDZ remain evacuated due to the life-threatening hazards of pyroclastic density currents, ballistic projectiles, rockfalls, volcanic gases, and other materials that could be generated by similar minor explosive eruptions.
It added that local government units must continue to prepare their communities within the PDC hazard zone for possible evacuation in case unrest suddenly escalates and a hazardous, worst-case explosive eruption becomes imminent.
Phivolcs also urged civil aviation authorities to advise pilots to avoid flying close to the volcano’s summit, as ash and ballistic fragments from sudden explosive eruptions can be extremely hazardous to aircraft.
Moreover, Office of Civil Defense–Negros Island Region (OCD-NIR) Director Donato Sermeno III said in a statement that no preemptive evacuation has been advised, as Alert Level 2 has been maintained by Phivolcs.
“Rest assured that our response clusters are on standby, and search and rescue units are prepared to mobilize in case of an escalation in the alert level,” he said.
Sermeno urged residents in affected areas to coordinate with their respective Disaster Risk Reduction and Management (DRRM) offices should they choose to evacuate. (MAP)