The Philippine Institute of Volcanology and Seismology warned Monday of a heightened likelihood of increasing magmatic activity at Kanlaon Volcano following the appearance of a visible crater glow, locally known as “banaag.”

In an advisory issued at 1:30 a.m., PHIVOLCS said emissions of superheated volcanic gas plumes were detected from the volcano’s summit crater.

Personnel from the Kanlaon Volcano Observatory in Negros Occidental reported that incandescence was observed with the naked eye for the first time at 7 p.m. Saturday.

Volcanologists described the “banaag” phenomenon as a common precursor to a magmatic eruption at Kanlaon Volcano.

PHIVOLCS said superheated gas activity had been monitored from November 2024 to April 2026 and had become more frequent during that period.

The agency added that seismic activity remained steady at an average of six volcano-tectonic earthquakes per day. Sulfur dioxide emissions, based on campaign mDOAS measurements, averaged 1,646 metric tons per day and increased slightly to 2,382 metric tons per day over the past week.

Kanlaon Volcano remains under Alert Level 2, indicating moderate volcanic unrest. PHIVOLCS said the alert status could be raised to Alert Level 3, which signifies heightened unrest, if signs of a magmatic eruption become evident.