Phivolcs detects increase in Kanlaon Volcano’s seismic activity; still on Alert Level 1

The Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday, Sept. 6 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 Kanlaon Volcano over the past 24 hours.

The Kanlaon Volcano Network recorded 36 volcanic earthquakes, Phivolcs said in an advisory issued at 9 a.m. on Wednesday.

Thirty-four of these were volcano-tectonic earthquakes were observed from 5 a.m. on Sept. 4 to 7:50 a.m. on Sept. 6.

The earthquakes have magnitudes ranging from 0.8 to 3.4 and depths ranging from zero to nine kilometers beneath the northeast portion of the Kanlaon range.

Phivolcs noted that while a constant "shallow" hydrothermal activity due to the degassing of deep magma have been monitored in the past months, the continous volcanic tectonic earthquake is said to be a sign of "fracturing at deeper levels" which probably further the volcanic unrest. 

The Kanlaon Volcano Network also recorded a daily sulfur dioxide average of 412 tons when it was last measured on Aug. 20. This is less than the average of 623 tons per day in July 2023.

As of Wednesday, Kanlaon Volcano remains on Alert Level 1.

"Should the uptrend in monitoring parameters persist, the volcano may be raised to Alert Level 2 to warn of increasing unrest,” Phivolcs warned. (Lizst Torres Abello)