- GILBERT BAYORAN
The Philippine Institute of Volcanology and Seismology (Phivolcs) reported July 21 an increase in seismic activity noted at the Kanlaon Volcano in Negros Island.
Phivolcs has monitored 35 volcano-tectonic earthquakes from 10 p.m. Thursday to 9:06 a.m. Friday. These earthquakes, ranging from magnitudes 0.9 to 2.3, were 12 to 15 kilometers deep beneath the summit crater.
Volcano-tectonic earthquakes occur near or beneath volcanoes. These are produced when rocks beneath or around the volcano move due to pressure from magma.
Based on Phivolcs’ advisory, the ongoing seismic activity indicates that fracturing at deeper levels is occurring and may possibly lead to further unrest.
It added that a slight increase in sulfur dioxide (S02) emission, and short-term inflation (bulging) of the slopes of Kanlaon, have also been observed.
Negrenses are reminded that Alert Level 1 still prevails over Kanlaon.
Should the uptrend in monitoring parameters persists, the volcano status may be raised to Alert Level 2 to warn of increasing unrest, the Phivolcs said.
It also strongly advised the 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./GB
