• GILBERT P. BAYORAN
The surge in tremors at Kanlaon Volcano continues as the Philippine Institute of Volcanology and Seismology recorded 72 volcano-tectonic (VT) earthquakes as of 8 a.m. yesterday.
The strongest VT earthquake was felt at Intensity 1 in La Carlota City, Negros Occidental and Canlaon City, Negros Oriental, according to the Phivolcs advisory.
Ma. Antonia Bornas, chief of Phivolcs Monitoring and Eruption Prediction Division, said the VT swarms, caused by rock fracturing beneath the volcano, indicates an upward movement of magma or magmatic gas, with intrusion from the 15-kilometer depth to the surface.
“As we always say, meron po tayong ini-expect na major eruption ng volcano (we expect a major eruption), but medyo mahaba po ang period of unrest (but the period of unrest may take long), it could take years bago mangyari ‘yon (before it happens),” Bornas said.
In an advisory, Phivolcs said the blockade of gas emission may result in pressurization and swelling of the edifice potentially leading to moderately explosive eruption.
Bornas recalled that while VT swarms also happened at Kanlaon Volcano in September last year, no eruption had taken place.
Then in October, ash emissions started, which was followed by an eruption on December 9, she added.
Bornas admitted that it is difficult to assess if there is an immediate eruption at Kanlaon Volcano.
“Definitely, there is always a chance for a moderate size eruption. But if you look at what happened last year, the eruption did not follow immediately,” she said.
Should there be a volcanic activity, there should be no human activity within the four-kilometer permanent danger zone.
Amid the VT swarm quakes, Bornas said there is no advice yet on the immediate evacuation of those residing within the six-kilometer extended danger zone.
Bornas clarified that the earthquakes experienced by some local government units in the past two days in central Negros has nothing to do with the Kanlaon restiveness as these were tectonic in origin.
Alert Level 2 remains hoisted over Kanlaon Volcano. | GB
