Increased seismic activity logged in Kanlaon

MANILA, Philippines — State seismologists have noted an increase in the seismic activity of Kanlaon Volcano on Negros Island, recording 72 volcanic earthquakes in the past 24 hours.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said the quakes occurred from midnight to noon yesterday.

On Sunday, Phivolcs recorded up to 135 volcanic quakes, including one that was described as a “relatively strong volcanic-tectonic earthquake.”

“Volcanic-tectonic earthquakes are generated by rock fracturing processes. The increase in such activity indicates progressive rock fracturing beneath the volcano as rising magma or magmatic gas drives a path toward the surface,” Phivolcs said.

State seismologist said sulfur dioxide emissions from the summit crater of the volcano average 554 tons per day.

“There has been a decline in the average sulfur dioxide emissions, from 4,144 (tons) since June 3 to 2,114 since April 1,” Phivolcs said.

State seismologists said these parameters indicate that the blockage of volcanic gas emission or closed-system degassing may result in pressurization and swelling of the edifice, and may lead to a moderately explosive eruption.

Alert Level 3 remains hoisted over Kanlaon, which means the volcano is in a state of magmatic unrest.

Phivolcs recommended that communities within the six-kilometer radius from the summit crater should remain unoccupied due to risks posed by pyroclastic density currents, ballistic projectiles, ashfall, rockfall and other related hazards.

Local government units have been advised to continue preparing vulnerable communities in case the volcano’s activity escalates.