State volcanologists have warned the public against entering Kanlaon Volcano’s four-kilometer permanent danger zone (PDZ) after visible crater glow was observed at the summit, a phenomenon that may indicate rising volcanic activity.
Mari-Andylene Quintia, resident volcanologist of the Kanlaon Volcano Observatory (KVO) in La Carlota City, Negros Occidental, said the crater glow observed Sunday evening could persist and may signal possible magmatic activity if it becomes sustained or intensifies.
“The crater glow seen Sunday might persist. If it is sustained or intensifies, that might be an indication of a magmatic eruption,” Quintia said in an interview.
She warned that volcanic hazards could be generated if an eruption occurs and reiterated calls for the public to stay away from the PDZ.
“We warn the public not to enter the PDZ,” she added.
In an advisory issued Monday morning, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said visible incandescence at Kanlaon’s summit crater was observed around 7 p.m. Sunday, marking the first time the phenomenon had been seen by the naked eye.
PHIVOLCS said the glow was caused by superheated volcanic gas and was later confirmed through reports from nearby residents.
The agency said the phenomenon, locally known as “banaag,” has also been observed before periods of increased volcanic activity at other volcanoes, including Mayon.
Despite the development, PHIVOLCS said monitoring parameters have remained generally consistent since Kanlaon’s moderately explosive eruption on March 15, 2026.
Alert Level 2 remains in effect over the volcano, although the agency warned that the alert status could be raised should the crater glow become sustained and intensify further.
PHIVOLCS also urged local government units and disaster officials to prepare response measures for vulnerable communities and remain alert for possible lahars and sediment-laden flows during heavy rainfall.