The Philippine Institute of Volcanology and Seismology on Wednesday logged an increase in seismic activity of Kanlaon Volcano in Negros Island.

Phivolcs said the Alert Level 1 status of the Kanlaon volcano remains but it may be raised to Alert Level 2 should the unrest intensifies.

A total of 36 volcanic earthquakes, including 34 volcano-tectonic tremors, in the Kanlaon volcano network were observed from 5 a.m. on Monday until 7 a.m. on Wednesday this week.

These earthquakes ranged in energy from ML0.8 to ML3.4 and occurred at depths of 0 to 9 kilometers beneath the northeast flank of the Kanlaon range.

Ground deformation data from continuous GPS and electronic tilt measurements have been recording short-term inflation of the middle slopes since March 2023 and longer-term inflation of the entire edifice since March 2022.

Phivolcs advised the public and the concerned local government units of Negros Island to be on alert for a possible phreatic eruption after detecting an increase in seismic activity at the volcano over the past 24 hours.

The Kanlaon's volcanic sulfur dioxide (SO2) gas emission from the summit crater averaged 412 tons per day on 20 August 2023 — lower than the average emission of 623 tons/day last July 2023.

While monitoring parameters in the past months have been consistent with shallow hydrothermal activity driven by degassing of deeper magma, Phivolcs explained that the ongoing volcanic-tectonic earthquake activity indicates that fracturing at deeper levels is occurring and may possibly lead to further unrest.

Thus, Phivolcs is not ruling out the possibility that the volcano status may be raised to Alert Level 2 to warn of increasing unrest should the monitored parameters persist in the coming days.

With its current conditions, Phivolcs said the volcano may pose sudden steam-driven explosions or phreatic eruptions without warning.

Hence, the public and local government units are strongly advised to be vigilant and refrain from entering the 4-kilometer Permanent Danger Zone.