The Philippine Institute of Volcanology and Seismology (Phivolcs) reported 28 volcanic earthquakes and three ashing events at Kanlaon Volcano on Saturday, Nov. 9.
In an advisory, Phivolcs noted that continuous degassing with occasional weak ash emissions has been occurring from Kanlaon Volcano's summit crater since Oct. 19.
Citing visual observations from the Kanlaon Volcano Network (KVN), Phivolcs reported 28 ash emission episodes lasting between four minutes and one hour and 18 minutes. These events produced grayish plumes rising 300 to 800 meters above the summit before drifting westward.
Phivolcs described the ash emissions as generally “quiet” or occurring without associated seismic or infrasound signals.
The most recent event occurred this morning, from 5:46 a.m. to 7:02 a.m., lasting one hour and 16 minutes based on visual observation.
“This event generated light-gray plumes rising 750 meters above the crater before drifting southwest,” Phivolcs said.
Meanwhile, traces of ashfall were reported in Sitio Bais, Barangay Yubo, La Carlota City, and Barangay Sag-ang, La Castellana. Residents of Barangay Yubo and Barangay Sag-ang also reported experiencing sulfurous fumes.
What the ash samples reveal
Phivolcs noted that a microscopic examination of ash samples from the Oct. 19 and Nov. 2 and 5 events indicated that the ash is primarily composed of pulverized old rock from within the edifice, not from new magma.
Additionally, Phivolcs reported that sulfur dioxide (SO₂) emissions from Kanlaon's summit crater averaged 4,701 tonnes per day.
Since an eruption on June 3 of this year, Kanlaon has persistently released high concentrations of volcanic SO₂, with a current average rate of 4,299 tonnes per day.
Increasing unrest
Phivolcs reminded the public that Kanlaon remains under Alert Level 2 (Increasing Unrest).
The agency cautioned that current activity at the summit crater may lead to eruptive unrest, potentially warranting an increase in the alert level.
The public was strongly advised to remain vigilant and avoid entry into the four-kilometer-radius Permanent Danger Zone (PDZ) to minimize risks from volcanic hazards, including pyroclastic density currents, ballistic projectiles, and rockfall.
“In the event of ashfall affecting communities downwind of Kanlaon’s crater, people should cover their nose and mouth with a damp, clean cloth or dust mask,” Phivolcs advised.
Phivolcs also urged civil aviation authorities to advise pilots to avoid flying close to the volcano’s summit, as ash and ballistic fragments from sudden eruptions can pose serious risks to aircraft.
Additionally, communities along river systems on the southern and western slopes, especially those prone to lahars and muddy streamflows, should take precautionary measures when heavy rainfall is forecasted or has begun.