THE Philippine Institute of Volcanology and Seismology (Phivolcs) on Saturday, January 11, 2025, has raised alarms following significant ground deformation at Kanlaon Volcano, located on the island of Negros.
Ground deformation refers to the changes on the surface of a volcano due to magma movement underneath the surface, Phivolcs said.
In its 2 p.m. Kanlaon Volcano advisory, Phivolcs said monitoring data from the Kanlaon Volcano Network revealed an increase in inflation or swelling in the middle to upper portion of the volcano’s eastern edifice since Friday evening. This sudden change in ground movement suggests a rapid pressurization within the volcano, raising concerns about a possible eruption.
Phivolcs noted that electronic tilt data from the Upper Pantao Observation Station, situated at 1,056 meters on the eastern flank of the volcano, showed a sharp increase in inflationary tilt at around 7:20 p.m. on January 10. This rapid deformation is seen as a potential precursor to magmatic activity, similar to the lead-up to the December 9, 2024 eruption.
Electronic Distance Meter (EDM) measurements have also tracked sustained inflation on the southeastern flank since late December 2024, while deflation on the western flank has been observed since early January 2025. These patterns mirror those recorded just before the December eruption, which was also preceded by a notable decline in sulfur dioxide (SO2) emissions.
SO2 emissions, an important indicator of volcanic activity, were recorded at an average of 5,763 metric tons per day on January 10, close to the average levels since the eruption in June 2024. However, a significant drop to 2,029 metric tons per day was observed the day before, on January 9, signaling potential changes in volcanic behavior.
As a result, Phivolcs has issued a Notice of Increased Ground Deformation and warned that the volcano remains at Alert Level 3 for magmatic unrest, an increased chance of sudden explosive eruptions. This could pose life-threatening hazards to nearby communities.
The public is urged to stay vigilant, with authorities recommending that all residents within a six-kilometer radius of the summit crater remain evacuated. This is due to the risk of pyroclastic density currents, ballistic projectiles, ashfall, lava flows, rockfalls, and other volcanic hazards.
In the event of heavy rainfall, there is a heightened risk of lahars, particularly in areas such as La Castellana and Canlaon City, which were impacted by such hazards in June 2024.
Residents in affected areas are urged to follow official advisories and stay informed about the evolving situation. (JGS/VoxPop Philippines)
