BACOLOD City – The Philippine Institute of Volcanology and Seismology (Phivolcs) has reported heightened seismic activity at Mount Kanlaon, recording a total of 72 volcano-tectonic (VT) earthquakes between 12 a.m. and 8 a.m. on Monday, September 15.
The tremors, ranging from magnitude 0.8 to 3.6, were traced at depths of 0 to 12 kilometers beneath the volcano’s northwestern flanks. The strongest quake was felt at Intensity I in La Carlota City, Negros Occidental, and Canlaon City, Negros Oriental.
Phivolcs explained that VT earthquakes are caused by rock fracturing, which suggests magma or magmatic gas is pushing upward, potentially creating a path to the surface.
Sulfur dioxide (SO₂) gas emissions from the summit crater averaged 2,338 tonnes per day on September 14, slightly below the medium-term average of 2,417 tonnes per day since January. Phivolcs warned that a possible blockage of gas emissions could cause pressurization and swelling of the volcano, which may lead to a moderately explosive eruption.
Kanlaon remains under Alert Level 2, indicating increased unrest. Phivolcs cautioned that the surge in VT events raises the possibility of steam-driven or short-lived explosive eruptions at the summit, which could trigger life-threatening hazards such as pyroclastic density currents (PDCs), ashfall, ballistic projectiles, and rockfalls.
Authorities strongly advised residents to strictly avoid the 4-kilometer Permanent Danger Zone (PDZ) and for communities within six kilometers of the summit to stay vigilant. Pilots were also warned against flying near the volcano due to the risk of sudden ash emissions hazardous to aircraft.
Phivolcs further reminded communities near rivers and streams to prepare for possible lahars and sediment-laden flows if heavy rains coincide with eruptive activity./PN
