PHIVOLCS observes 'increased seismic activity' at Kanlaon Volcano

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Tuesday monitored an increased seismic activity at Kanlaon Volcano on Negros Island.

In an advisory, PHIVOLCS said 36 volcanic earthquakes, including 34 volcano-tectonic (VT) earthquakes, have been recorded by the Kanlaon Volcano Network between 5 a.m. on September 4 and 7:50 a.m. on September 6.

"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," PHIVOLCS said.

Short-term inflation of the volcano's middle slopes has been recorded since March 2023, and longer-term inflation of the entire edifice since March 2022, it added.

PHIVOLCS also said volcanic sulfur dioxide (SO2) gas emission from the summit crater averaged 412 tonnes/day on August 20, 2023, which was lower than the average emission of 623 tonnes/day in July 2023.

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

Kanlaon is currently under Alert Level 1, but the alert level could be raised to 2 if the uptrend in monitoring parameters persists, according to state seismologists.

PHIVOLCS "strongly advised" public and local government units to be vigilant and refrain from entering the four-kilometer Permanent Danger Zone (PDZ) "due to increased chances of sudden and hazardous phreatic eruptions occurring without warning."

It also asked civil aviation authorities to advise pilots to avoid flying close to the volcano’s summit to avoid potential danger. —KBK, GMA Integrated News