The Philippine Institute of Volcanology and Seismology (Phivolcs) confirmed on Saturday, Oct. 19, that it has been monitoring “ashing” events at Kanlaon Volcano and noted that the current activity may lead to “eruptive unrest” and an increase in the alert level.
Citing the monitoring of the Kanlaon Volcano Network (KVN), Phivolcs said volcanic ash is being intermittently “entrained,” or carried out, by continuous degassing from Kanlaon’s summit crater.
In a volcano bulletin, Phivolcs also noted “brief volcanic ash events” at Kanlaon Volcano.
“Volcanic ash in the degassing plume signifies open vent conditions, where volcanic gas can carry fine debris from fractured rock or even from the margins of shallow magma beneath the edifice,” Phivolcs explained.
Phivolcs reported that, based on the visual monitors of the KVN, “brief episodes of gray ash being entrained or carried out by continuous degassing from the summit crater of Kanlaon” have been recorded.
These “ashing” events, Phivolcs said, were observed at 6:41 a.m., 7:01 a.m., and 8:01 a.m., lasting two to six minutes, based on visual observations.
“No detectable seismic or infrasound signals of these events were recorded,” Phivolcs added.
Phivolcs said that Alert Level 2 remains in effect over Kanlaon Volcano.
Ash emissions, degassing activity
Phivolcs explained that the events generated light gray plumes that rose 500 meters above the crater before drifting southwest.
Traces of ash were reported in Barangays Yubo and Ara-al in La Carlota City, and Barangay Sag-ang in La Castellana, Phivolcs noted.
Meanwhile, sulfurous fumes were also experienced in Barangay Yubo. “The summit crater was obscured by cloud cover, which hampered visual observations for the remainder of the morning,” it added.
Furthermore, Phivolcs noted that volcanic SO2 emissions from the summit crater of Kanlaon, based on campaign Flyspec measurements on Oct. 18, averaged 2,769 tonnes/day.
Phivolcs added that Kanlaon has been “degassing increased concentrations of volcanic SO2 this year at an average rate of 3,383 tonnes/day” before the June 3, 2024, eruption, but “emission since then has been particularly elevated, with a current average of 4,133 tonnes/day.”
Public reminder
Phivolcs reminded the public that while Alert Level 2, or increasing unrest, remains in effect over Kanlaon, the “current activity may lead to eruptive unrest and an increase in the Alert Level.”
Phivolcs strongly advised the public to remain “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, rockfalls, and others.”
“In the event of ashfall that may affect communities downwind of Kanlaon’s crater, people should cover their noses and mouths with a damp, clean cloth or dust mask,” Phivolcs said.
Phivolcs also advised civil aviation authorities to caution pilots against flying close to the volcano’s summit, as ash and ballistic fragments from sudden eruptions can be hazardous to aircraft.
Additionally, Phivolcs urged those living near river systems on the southern and western slopes, especially areas that have experienced lahars and muddy streamflows, to “take precautionary measures when heavy rainfall over the volcano is forecast or has begun.”
Kanlaon Volcano is located in the provinces of Negros Occidental and Negros Oriental.