The Philippine Institute of Volcanology and Seismology (Phivolcs) issued a notice of increased seismic activity at Kanlaon Volcano on Wednesday afternoon, July 3.
Ninety volcanic earthquakes were recorded by the Kanlaon Volcano Network between 3 p.m. Tuesday and 12 p.m. Wednesday, Phivolcs said.
Most of these earthquakes were generated within a depth of 20 kilometers beneath the southeastern sector of the edifice and consist of five volcano-tectonic events that are produced by rock fracturing, and eighty-five weak low-frequency events that indicate the movement of volcanic fluids, it said.
Phivolcs said the volcanic sulfur dioxide (SO2) gas emission from the summit crater has been persistently elevated since Kanlaon’s June 3 eruption averaging 3,254 tons per day since then, and reaching 5,083 tons on Tuesday.
Ground deformation data from continuous GPS and electronic tilt measurements have been recording an ongoing inflation that began between April and July 2023 and a longer-term inflation of the entire edifice since March 2022, indicating slow but sustained pressurization within the volcano, Phivolcs added.
The overall monitoring parameters indicate that magmatic processes beneath the volcano may be driving the current unrest, causing increased volcanic earthquake activity, persistently high concentrations of volcanic gas emission and swelling of the edifice, it said.
Phivolcs said the public is reminded that Alert Level 2 (increasing unrest) prevails over Kanlaon.
This means that there is current unrest driven by shallow magmatic processes that could eventually lead to explosive eruptions or even precede hazardous magmatic eruption at the summit crater, Phivolcs said.
The public is strongly advised to be vigilant and avoid entry into the four kilometer-radius Permanent Danger Zone to minimize risks from volcanic hazards such as pyroclastic density currents, ballistic projectiles, rockfall and others, it added.
In case of ash fall events that may affect communities downwind of Kanlaon’s crater, people should cover their nose and mouth with a damp, clean cloth or dust mask, Phivolcs said.
Communities living beside river systems on the southern and western slopes, especially those that have already experienced lahars and muddy streamflows, are advised to take precautionary measures when heavy rainfall over the volcano has been forecast or has begun, it added.*