An explosive eruption or more ash emission at Kanlaon Volcano has become more imminent with 85 volcano-tectonic (VT) earthquakes recorded from 12 a.m. Wednesday to 12 p.m. Thursday, October 16, a Philippine Institute of Volcanology and Seismology (Phivolcs) official said.
“The chances of such activity are increasing, it could happen any time, but we cannot predict when”, Ma. Antonia V. Bornas, Phivolcs Volcano Monitoring and Eruption Prediction Division chief, said.
“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 or PDCs, ballistic projectiles, ashfall and rockfall,” Phivolcs said in a notice of increased seismic activity on Thursday.
It is strongly recommended that communities within the 4-km Permanent Danger Zone (PDZ) strictly remain evacuated, and those within the 6-km radius from the summit crater be vigilant and ready in case unrest worsens, Bornas said.
Philippine National Police acting chief Lt Gen Jose Melencio Nartatez Jr. on Tuesday, Oct. 14, directed all police units under the Police Regional Office–Negros Island Region (PRO-NIR) to assist local government units in enforcing the 4-km. Permanent Danger Zone (PDZ) around Kanlaon Volcano.
The PRO NIR on Thursday said that it has deployed 106 personnel for round-the-clock monitoring and assistance operations amid the heightened unrest at Kanlaon.
Policemen have been deployed in La Castellana, Negros Occidental, and Canlaon City, Negros Oriental, to assist displaced families, maintain peace and order, border control, and ensure the protection of evacuees, particularly against gender-based violence, the PRO-NIR said.
There are 284 evacuees from the PDZ in six evacuation centers in Negros.
The recent earthquakes at Kanlaon ranged in strength between ML 0.1 and ML 2.9 and were generated at 0 to 6 kilometers depths beneath the northwestern flanks of the volcanic edifice, the Phivolcs said Thursday.
VTs are generated by rock fracturing processes, and the increase in activity strongly indicates progressive rock-fracturing beneath the volcano as rising magma or magmatic gas drives a path towards the surface, it said.
Volcanic sulfur dioxide gas emissions from the summit crater on Wednesday averaged 1,879 tons, Phivolcs added.
“These parameters indicate that the blockage of volcanic gas emission (or closed-system degassing) may result in pressurization and swelling of the edifice, potentially leading to a moderately explosive eruption,” it said.
The public is reminded that Alert Level 2 prevails over Kanlaon, which means that the volcano is in a state of increased unrest, Phivolcs said.
The Phivolcs 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, it added.*