The Philippine Institute of Volcanology and Seismology (Phivolcs) has noticed an increased seismic activity at Mount Kanlaon, which logged a total of 90 volcanic earthquakes based on latest monitoring.

In an advisory released Wednesday, Philvocs said most of these tremors were generated within a depth of 20 kilometers beneath the southeastern sector of the edifice.

It consisted of five volcano-tectonic events that were produced by rock fracturing and 85 weak low-frequency events that indicated the movement of volcanic fluids.

“In addition, volcanic sulfur dioxide (SO2) gas emission from the summit crater has been persistently elevated since the 03 June 2024 eruption, currently averaging 3,254 tonnes/day since then and reaching 5,083 tonnes/day yesterday,” the agency said.

The overall monitoring parameters indicate that magmatic processes beneath the volcano may be driving current unrest, causing increased volcanic earthquake activity, persistently high concentrations of volcanic gas emission and swelling of the edifice.

“The public is reminded that Alert Level 2 (increasing unrest) prevails over Kanlaon. This means that there is current unrest driven by shallow magmatic processes that could eventually lead to explosive eruptions or even precede hazardous magmatic eruptions at the summit crater,” Phivolcs warned.

Entry into the four kilometer-radius Permanent Danger Zone (PDZ) remains prohibited to minimize risks from volcanic hazards such as pyroclastic density currents, ballistic projectiles, rockfall and others.

Kanlaon exploded last June 3, which triggered volcanic ashfall and mudflow, affecting nearby communities who were forced to seek temporary shelter elsewhere.