The Philippine Institute of Volcanology and Seismology (Phivolcs) on Saturday, Jan. 11, reported “increased ground deformation” at Kanlaon Volcano and noted that the overall parameters suggest pressurization, which could lead to an eruption “broadly similar” to last month's event.
In a bulletin, Phivolcs noted that ground deformation monitoring by the Kanlaon Volcano Network (KVN) has recorded a “pronounced inflation or swelling of the middle to upper portion of the eastern edifice” since the evening of Jan. 10.
Phivolcs said that electronic tilt measurements recorded by the Upper Pantao Observation Station (VKUP) at 1,056 meters elevation on the eastern flank of the volcano “showed an abrupt and sharp increase in inflationary tilt” beginning at 7:20 p.m. on Jan. 10.
This, Phivolcs said, indicated a “sudden pressurization within the upper portions of the edifice” of Kanlaon Volcano.
Phivolcs explained that the Electronic Distance Meter (EDM) measurements by the Kanlaon Volcano Observatory have been tracking the “inflation of the southeastern flank” since the last week of December 2024 and the deflation of the western flank since the first week of 2025.
These ground deformation parameters, Phivolcs noted, are “largely similar” to those recorded before the eruption on Dec. 9, 2024, which was also preceded by a drop in sulfur dioxide (SO2) emissions.
Phivolcs observed that campaign SO2 measurements on Jan. 10 averaged 5,763 tons per day, which is “close to average emissions” since the eruption on June 3, 2024. However, a “significant drop” to 2,029 tons per day was recorded on Jan. 9, 2025.
Another possible eruption
Phivolcs explained that the “overall parameters may indicate that the shallow magma conduit of the volcano is undergoing pressurization that may lead to an eruption” broadly similar to the Dec. 9, 2024, event.
Kanlaon Volcano, Phivolcs reminded, remains under Alert Level 3 status, indicating “magmatic unrest.”
“There is presently an increased chance for sudden explosive eruptions to occur, endangering communities at risk with life-threatening volcanic hazards,” Phivolcs said.
Potential evacuation
Phivolcs reminded communities within a six-kilometer radius of the summit crater to “remain evacuated” due to the danger of pyroclastic density currents (PDCs), ballistic projectiles, ashfall, lava flows, rockfalls, and other related hazards.
Moreover, Phivolcs urged local government units (LGUs) and disaster risk reduction and management (DRRM) councils to monitor weather conditions vigilantly, especially in case of heavy rainfall, which could generate lahars and sediment-laden streamflows in channels draining the southern flanks of the volcano.
Phivolcs noted that the barangays of La Castellana and Canlaon City — which have been impacted by PDCs — as well as barangays downstream, especially those that experienced lahars and muddy streamflows in June 2024, could be affected by channel-confined lahars in case of heavy rains.
Civil aviation authorities, Phivolcs said, must also advise pilots to “avoid flying close” to the volcano’s summit, as ash from any sudden eruption can be hazardous to aircraft.
Phivolcs further advised LGUs and DRRM councils to “prepare” communities within the DOST-Phivolcs Pyroclastic Density Currents Hazard Map for “potential evacuation in case unrest further escalates and a hazardous, worst-case explosive eruption becomes imminent.”