Phivolcs may raise Kanlaon's alert status due to increased seismic events

MANILA, Philippines: The alert level in Kanlaon Volcano may be raised to 2 after the Philippine Institute of Volcanology and Seismology (Phivolcs) recorded an increase in seismic events in the area, including gas emissions.

Phivolcs director Teresito «Toto» Bacolcol told The Manila Times that they issued a notice following the latest data from the Kanlaon Volcano Network (KVN) which showed a total of 15 volcano-tectonic or VT earthquakes recorded between 3:58 a.m. and 5 a.m. on Wednesday.

Mt. Kanlaon in Negros Island — PNA-Bacolod file photo

«These earthquakes ranged in energy from magnitude 1.4 to magnitude 4.2 and occurred at depths of 0 to two kilometers beneath the northern flank of the Kanlaon range,» Bacolcol said.

Also, the sulfur dioxide (SO2) gas emission from the volcano's summit crater has risen since May 1, 2023, averaging 570 tons/day since then with the latest SO2 measurement on November 14 at 1,017 tons/day, he said.

The KVN said that shorter-term inflation of the southwestern middle slopes and longer-term inflation of the entire edifice since March 2022 have also been recorded.

While monitoring parameters in the past months have been consistent with shallow hydrothermal activity driven by degassing of deeper magma, on-going VT earthquake activity indicates shallow rock-fracturing on the edifice which may lead to further unrest, Bacolcol said.

He reiterated that the Negros volcano is currently under Alert Level 1.

«Should the above uptrend in monitoring parameters persist, the volcano status may be raised to Alert Level 2 to warn of increasing unrest,» the Phivolcs chief said.

The four-kilometer Permanent Danger Zone must remain free from the public due to increased chances of sudden and hazardous phreatic eruptions occurring without warning, Bacolcol said.

Also, civil aviation authorities were expected to advise pilots to avoid flying close to the volcano's summit as sudden phreatic eruption can be hazardous to the aircraft, he added.