The Philippine Institute of Volcanology and Seismology (Phivolcs) confirmed on Saturday, October 25, that Kanlaon Volcano recorded three ash emission events at its summit crater.
Based on time-lapse footage from the Kanlaon Volcano Observatory in Canlaon City, Phivolcs said the ash emissions occurred at 7:04 a.m., 8:26 a.m., and 9:23 a.m., producing grayish plumes that rose up to 300 meters above the crater before drifting northwest.
The agency said the activity, captured through the observatory's IP camera, confirms ongoing volcanic unrest within the summit crater.
October 24 eruption
Kanlaon Volcano, which straddles the provinces of Negros Occidental and Negros Oriental, is one of the most active volcanoes in the Philippines.
It last recorded a moderately explosive eruption on October 24, generating a plume that rose up to 2,000 meters above the summit. The eruption, which began at 8:05 p.m. and lasted for three minutes, was accompanied by a dense incandescent plume and a booming sound heard within a six-kilometer radius of the volcano.
Provincial and local authorities reported ashfall in several areas of Negros Occidental, including Bago City (Barangays Mailum, Ma-ao, Ilijan, Bacong, and Abuanan), La Carlota City (Barangays Ara-al and Sto. Guintubdan), and Pontevedra (Barangay Zamora).
Residents in La Castellana, Negros Occidental, and Canlaon City, Negros Oriental, also reported strong sulfurous fumes, particularly in Barangays Cabagnaan, Linothangan, Malaiba, and Pula.
Phivolcs confirmed that incandescent pyroclastic density currents (PDCs) descended the volcano's southern slopes within one kilometer of the crater, based on visual and thermal camera monitoring.
Volcanic activity and gas emissions
Phivolcs noted that the October 24 eruption followed a period of heightened activity, marked by 19 ash emission events between September 8 and October 23, and volcanic earthquake swarms that peaked at 90 events on October 16.
Prior to the eruption, the volcano's sulfur dioxide (SO₂) emissions dropped significantly to 189 tonnes per day, well below the October average of 1,699 tonnes per day and the long-term average of 3,119 tonnes per day since June 2024.
Phivolcs explained that this "closed-system degassing" likely caused internal pressure buildup, leading to the eruption -- a mechanism consistent with Kanlaon's past explosive activity observed since June 2024.
Alert Level 2 maintained; further eruptions possible
Phivolcs reminded the public that Alert Level 2 (Increased Unrest) remains in effect over Kanlaon Volcano.
This means there is ongoing unrest driven by shallow magmatic or hydrothermal processes, which could result in minor explosions or phreatic eruptions.
Communities and local governments near the volcano are advised to remain vigilant and avoid entry into the 4-kilometer Permanent Danger Zone (PDZ) due to possible sudden steam-driven explosions and ashfall.
Phivolcs noted that no significant increase in volcanic earthquakes or ground deformation has been detected.
However, the agency warned that further moderate explosive eruptions or ash emissions remain possible, which could generate hazardous pyroclastic flows, ballistic fragments, or ashfall within the PDZ and toward communities west of the volcano.
Phivolcs assured the public that it is closely monitoring Kanlaon Volcano's activity and will issue updates immediately should new developments arise.