The Philippine Institute of Volcanology and Seismology warned that it recorded the highest emission of volcanic gas at Kanlaon Volcano since instrumental gas monitoring began, on Friday, June 28.
Volcanic sulfur dioxide (SO2) gas emission from the summit crater of Kanlaon based on campaign Flyspec measurements averaged 5,397 tons on Friday, Phivolcs said in an advisory.
“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.
Kanlaon has been degassing increased concentrations of volcanic SO2 this year at an average rate of 1,897 tons/day, but emission since its June 3 eruption has been particularly elevated at an average of 3,175 tons per day, it added.
The volcanic earthquake activity at Kanlaon has persisted at an average of 10 events/day since the eruption, Phivolcs said.
Ground deformation data from continuous GPS and electronic tilt measurements have been recording medium-term inflation of the Kanlaon edifice since March 2022, and a shorter-term inflation of the eastern flank since 2023, indicating slow but sustained pressurization within the volcano, it said.
The overall monitoring parameters indicate that magmatic processes beneath volcano may be driving current unrest, causing persistently high concentrations of volcanic gas emission, swelling of the edifice and occasional volcanic earthquake activity.
The public is reminded that Alert Level 2 (increasing unrest) remains over Kanlaon, Phivolcs said.
The public is strongly advised to be vigilant and 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, Phivolcs said.
It reiterated that 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.
Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash and ballistic fragments from sudden eruption can be hazardous to aircraft, Phivolcs reiterated.
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.*