The Philippine Institute of Volcanology and Seismology issued a notice of increased volcanic-tectonic (VT) earthquakes at Kanlaon Volcano in Negros Island Thursday, Oct. 31, which could lead to an eruption.
Mari-Andylene Quintia, Phivolcs resident volcanologist at the Kanlaon Volcano Observatory, said 64 VT earthquakes were recorded by the Kanlaon Volcano Network since 12 a.m. Thursday and they issued an advisory to warn the public of a possible eruption.
These VT earthquakes ranged in strength between ML0.9 and ML2.9 and were generated at 2 to 8 kilometers depths beneath the western flanks of the volcanic edifice, a Phivolcs advisory said.
VT earthquakes are generated by rock fracturing processes and the increase in activity strongly indicates progressive rock-fracturing beneath the volcano as rising magma drives a path towards the surface, it said.
Volcanic sulfur dioxide (SO2) gas emission from the summit crater of Kanlaon is also at an elevated level with 7,087 tons recorded on Wednesday, Quintia said.
Kanlaon has been degassing increased concentrations of volcanic SO2 this year at an average rate of 1,273 tons per day prior to its June 3 eruption, she said.
But emission since then has been particularly elevated at a current average of 4,234 per day, she added.
The Phivolcs advisory reminded the public that Alert Level 2 (increasing unrest) prevails over Kanlaon, but that current seismic activity may lead to eruptive unrest and an increase in the alert level.
The public is strongly advised to be ready and vigilant, and to avoid entry into the four kilometer-radius Permanent Danger Zone (PDZ) to minimize risks from volcanic hazards such as pyroclastic density currents, ballistic projectiles, rockfall and others, it said.
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 added.
Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash and ballistic fragments from a sudden eruption can be hazardous to aircraft, it said.*