The state seismologist on Wednesday said Kanlaon Volcano in Negros Island have been exhibiting increased seismic activity.
In its advisory, Phivolcs said it recorded 36 volcanic earthquakes, including 34 volcano-tectonic (VT) earthquakes that occured between 5 AM on Sept. 4 and 7:50 AM on Sept. 6.
The said earthquakes have energy ranging from ML0.8 to ML3.4 and a depth of 0 to 9 kilometers beneath the volcano's northeast flank.
"Ground deformation data from continuous GPS and electronic tilt measurements have been recording short-term inflation of the middle slopes since March 2023 and a longer-term inflation of the entire edifice since March 2022," the state seismologic said.
Phivolcs said Kanlaon also emitted 412 tonnes of volcanic sulfur dioxide (SO2) gas emission on August 20, slightly below the 623 tonnes per day average emission recorded a month prior.
The state seismologist retained the Alert Level 1 status in the volcano but warned of the possibility of upgrading this to Alert Level 2 once increased activities continue.
Entry into the four-kilometer Permanent Danger Zone (PDZ) is still prohibited "due to increased chances of sudden and hazardous phreatic eruptions occurring without warning."
"Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ejecta from any sudden phreatic eruption can be hazardous to aircraft," Phivolcs added.
