• GILBERT P. BAYORAN
After recording elevated volcanic sulfur dioxide (SO2) gas emissions from the crater of Kanlaon, the Philippine Institute of Volcanology and Seismology has also noticed an increase in seismic activity of the volcano.
A total of ninety volcanic earthquakes have been recorded by the Kanlaon Volcano Network between 3:00 p.m. of July 2 to 12:00 noon of July 3.
Most of these earthquakes, according to PHIVOLCS, were generated within a depth of 20 kilometers beneath the southeastern sector of the edifice, and consist of five volcano-tectonic events, that are produced by rock fracturing and eighty-five weak low-frequency events that indicate the movement of volcanic fluids.
In addition, volcanic sulfur dioxide (SO2) gas emissions from the summit crater have been persistently elevated since the June 3 eruption, currently averaging 3,254 tonnes/day since then, and reaching 5,083 tonnes/day on July 2, the PHIVOLCS advisory further said.
The normal volcanic sulfur dioxide gas emissions at Kanlaon is 300 tons a day.
Ground deformation data from continuous GPS and electronic tilt measurements have been recording an ongoing inflation that began between April and July 2023 and a longer-term inflation of the entire edifice since March 2022, indicating slow but sustained pressurization within the volcano.
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, PHIVOLCS further stated.
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, it added.
It also reminded the public that Alert Level 2 (increasing unrest) prevails over Kanlaon, and discouraged the entry into the four kilometer-radius Permanent Danger Zone (PDZ) to minimize risks from volcanic hazards such as pyroclastic density currents, ballistic projectiles, rockfall and others.*
