ILOILO City – There could be further explosive eruptions at Kanlaon Volcano, warned the Philippine Institute of Volcanology and Seismology (Phivolcs). It urged local governments and agencies concerned to strictly enforce the four-kilometer radius Permanent Danger Zone (PDZ) around the volcano straddling Negros Occidental and Negros Oriental.
The PDZ covers barangays Ara-al and Yubo in La Carlota City; barangays Sag-ang, Mansalanao, Cabagnaan, and Biaknabato in La Castellaña town; Barangay Minoyan in Murcia town; and Barangay Codcod in San Carlos City, all in Negros Occidental; and barangays Pula and Lumapao in Canlaon City in Negros Oriental.
Kanlaon is an active stratovolcano and the highest mountain on the island of Negros, as well as the highest peak in the Visayas, with an elevation of 2,465 meters (8,087 feet) above sea level.
According to Ma. Antonia Bornas, chief, Volcano Monitoring and Eruption Prediction Division of Phivolcs, the chances of explosive eruptions occurring are significant, thus increasing the threat of volcanic hazards such as pyroclastic density currents or PDCs and ballistic projectiles within the PDZ.
PDCs are made up of fragmented volcanic particles, gases, and ash that travel down volcanic slopes at high speeds.
Civil aviation authorities must warm aircraft to avoid flying close to the Kanlaon summit, added Bornas and Dr. Ma. Mylene Villegas, director III at the Department of Science and Technology (DOST) and Phivolcs.
Kanlaon Volcano is approximately 30 kilometers southeast of Bacolod City, the capital and most populous city of Negros Occidental and whole island.
Phivolcs has three current outlooks for Kanlaon Volcano. These are the following:
* If monitoring parameters are sustained, phreatic and short-lived explosive eruptions may subsequently occur and produce small-magnitude hazards that will endanger areas within the PDZ. Unrest is likely caused by hydrothermal processes driven by magmatic degassing deep within the volcanic edifice. Alert Level 2 will be maintained until such time that monitoring parameters significantly change.
* If seismic, ground deformation and volcanic gas parameters worsen, magmatic eruption may become likely. Current unrest likely being driven by stresses within the volcanic edifice produced by rising magma. Eruptive activity could generate volcanic hazards that will endanger areas within the lava flow and PDC hazard zones delineated by DOST-PHILVOCS. Alert Level 3 will be raised.
* If monitoring parameters decline, unrest is driven by very shallow hydrothermal processes. Alert Level will step down to Alert Level 1 after sufficient observation has elapsed.
The volcano is a favorite spot for mountain climbers and is the centerpiece of Mount Kanlaon Natural Park, a national park originally established on August 8, 1934.
Around 8 p.m. on Monday, Phivolcs raised the volcano’s alert to Level 2 a little over an hour after Kanlaon’s phreatic or steam-driven eruption. This means there is current unrest driven by shallow magmatic processes that could eventually lead to further explosive eruptions or even precede hazardous magmatic eruption.
The public is strongly advised to be vigilant and avoid the four-kilometer-radius PDZ to minimize risks from sudden explosions, rockfalls and landslides.
In case of ash fall events that may affect communities downwind of Kanlaon’s crater, people should cover their nose and mouth with a damp, clean cloth or dust mask.
Civil aviation authorities were advised to warn pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft.
Monday night’s eruption produced a voluminous and incandescent plume that rapidly rose to 5,000 meters above the vent and probable short PDCs approximately two to three kilometers down the southern and southeastern slopes.
The eruption lasted six minutes based on the seismic record and was preceded by a relatively strong volcano-tectonic earthquake.
Reports of coarse ashfall and sulfurous odor have been reported in communities on western slopes of the volcano.
Kanlaon has been exhibiting above background earthquake activity for the past month./PN
