Phivolcs: Kanlaon showing slow, sustained inflation

THE Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday it has observed “pronounced increase” in the inflation or swelling of Kanlaon Volcano in Negros Island, indicating higher chances of “eruptive activity.”

In an advisory, Phivolcs said ground deformation monitoring of the volcano showed the pronounced increase in the past month.

Phivolcs said Kanlaon Volcano has been undergoing “slow but sustained” inflation since 2022. This, it said, indicated “a long-term pressurization within the volcano.”

“Considering that volcanic earthquake activity and elevated volcanic SO2 (sulfur dioxide) emission persists, the latest changes in ground deformation parameters could further indicate that magmatic intrusion beneath the edifice may be taking place, warning of increased chances of eruptive activity taking place,” Phivolcs also said.

Kanlaon Volcano had an “explosive eruption” last June 3, affecting over 50,000 individuals and causing some P150.96 million in damage to agriculture in the Western Visayas and Central Visayas regions.

The eruption prompted Phivolcs to raise the volcano’s alert status to Alert Level 2 (moderate level of volcanic unrest), from Level 1 (low level of volcanic unrest).

“The public is reminded that Alert Level 2 prevails over Kanlaon,” Phivolcs said in its advisory yesterday.

“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,” said Phivolcs.

It advised the public to be “vigilant” and avoid entry to the four-kilometer permanent danger zone “to minimize risks from volcanic hazards such as pyroclastic density currents, ballistic projectiles, rockfall and others.”

“Communities living beside river systems on the southern and western slopes, especially those that have already experienced lahars and muddy stream flows, are advised to take precautionary measures when heavy rainfall over the volcano has been forecast or has begun,” Phivolcs added.

It also urged civil aviation authorities to advise pilots “to avoid flying close to the volcano’s summit as ash and ballistic fragments from sudden