Negros authorities on alert as Kanlaon activity increases
BACOLOD CITY—The Disaster Risk Reduction and Management Offices (DRRMOs) in localities close to Mt. Kanlaon have gone on alert after the volcano showed renewed signs of restiveness on Sunday.
“We are in contact with Phivolcs (Philippine Institute of Volcanology and Seismology), alert level 2 remains, concerned DRRMOs are on alert,” Gov. Eugenio Jose Lacson said in an interview on Sunday.
“Prayers for all would be good,” he added.
The governor issued this statement on the same day that Office of Civil Defense-Negros Island Region Director Donato Sermeno III reminded local authorities to remain vigilant against the further escalation of increased seismic activity at Kanlaon that could require evacuations.
It has only been weeks since residents from within the danger zone of the volcano had been allowed to go home after staying in shelters since the volcano erupted on Dec. 9 last year.
“Whether we like it or not our barangays are always prepared for any eventuality,” said Mayor Añejo Nicor of La Castellana, one of the towns in Negros Occidental closest to Kanlaon.
He said everything appeared to be normal in his town on Sunday but they were not taking any chances and must be alert with Kanlaon still under alert level 2.
Phivolcs’ warning
Phivolcs on Sunday issued a notice of increased seismic activity at the volcano that could lead to eruptions.
A total of 41 volcano-tectonic (VT) earthquakes were recorded by the Kanlaon Volcano Network between 11 p.m. on Saturday and 10 a.m. on Sunday, according to Phivolcs.
The increase in VT events could lead to increased chances of steam-driven or phreatic eruptions or short-lived weak to moderately explosive eruptions occurring at the summit that could generate life-threatening volcanic hazards such as pyroclastic density currents, ballistic projectiles, ashfall and rockfall, it said.
The VTs ranged in strength between ML (local magnitude) 0.8 and ML 4.6 and were generated at 0 to 7 kilometers depths beneath the northwestern flanks of the volcanic edifice, Phivolcs said.
The VT earthquakes recorded between 3 a.m. and 2:30 p.m. on Sunday were of magnitude ranging from 2 to 4.7. The strongest of the VT quakes were felt at Intensity III in the cities of La Carlota City and Bacolod in Negros Occidental and Canlaon City in Negros Occidental, while lesser intensity quakes were felt in Bago City and the towns of Murcia, La Castellana, Salvador Benedicto and Moises Padilla in Negros Occidental.
VTs are generated by rock fracturing processes and the increase in VT activity strongly indicates progressive rock-fracturing beneath the volcano as rising magma or magmatic gas drives a path towards the surface, Phivolcs said.
Blockage
Phivolcs said these parameters indicated that the blockage of volcanic gas emission (or closed-system degassing) may result in pressurization and swelling of the edifice, potentially leading to moderately explosive eruption.
The agency reminded the public that alert level 2 still prevails over Kanlaon, which means that the volcano is in a state of increased unrest.
Phivolcs strongly recommended that communities within the 4-kilometer permanent danger zone were to strictly remain evacuated and those within the 6-km radius from the summit crater be vigilant and be ready to evacuate in case unrest worsens.
It also stressed the need for increased vigilance against potential syn-eruption lahars and sediment-laden streamflows in channels draining the edifice should intense rains occur during eruptive unrest.
Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft, Phivolcs said.
