Kanlaon Volcano under heavy cloud cover as seen from La Castellana, Negros Occidental, Sunday afternoon.* Marvin Escander photo
The Philippine Institute of Volcanology and Seismology (Phivolcs) on Sunday, Sept. 14, issued a notice of increased seismic activity at Kanlaon Volcano that could lead to an eruption.
Local authorities have been reminded “to remain vigilant against a further escalation of the situation that could require evacuations”, Director Donato Sermeno III of the Negros Island Region Office of Civil Defense also said.
“We are in contact with Phivolcs. Alert Level 2 remains and concerned DRRMOs (Disaster Risk Reduction and Management Offices) are on alert,” Negros Occidental Governor Eugenio Jose Lacson said.
“Prayers for all would be good”, Lacson said.
“Whether we like it or not, our barangays are always prepared for any eventuality,” La Castellana Mayor Añejo Nicor said.
Everything appears to be normal in his town, but they are not leaving anything to chance and must be alert, with Kanlaon still under Alert Level 2, he added.
A total of 41 volcano-tectonic (VT) earthquakes were recorded by the Kanlaon Volcano Network between 11 p.m. Saturday and 10 a.m. Sunday.
The increase in VT events could lead to a higher chance of steam-driven or phreatic eruptions, or short-lived, weak-to-moderately explosive eruptions at the summit. These could generate life-threatening volcanic hazards such as pyroclastic density currents (PDCs), ballistic projectiles, ashfall, and rockfall, Phivolcs said.
The VTs that ranged in strength between magnitude 0.8 to 4.6 were generated at 0 to 7 kilometers deep beneath the northwestern flanks of the volcanic edifice, Phivolcs said.
The strongest of these VT earthquakes were felt at Intensity III in La Carlota City and Bacolod City, Negros Occidental, and Canlaon City, Negros Oriental, as well as in Bago City, Murcia, and La Castellana in Negros Occidental, it added.
The increase in VT activity strongly indicates progressive rock fracturing beneath the volcano as rising magma or magmatic gas drives a path toward the surface, Phivolcs said.
Volcanic sulfur dioxide (SO2 ) gas emissions from the summit crater of Kanlaon on Saturday averaged 1,122 tons per day, which is lower than the medium-term average of 2,594 tons per day since January 1, it added.
These parameters indicate that the blockage of volcanic gas emission may result in pressurization and swelling of the edifice, potentially leading to a moderately explosive eruption, Phivolcs said.
The public is reminded that Alert Level 2 prevails over Kanlaon, which means the volcano is in a state of increased unrest.
Phivolcs strongly recommended that communities within the 4-km Permanent Danger Zone (PDZ) strictly remain evacuated and that those within the 6-km radius from the summit crater be vigilant and ready in case unrest worsens.
Phivolcs also stressed the need for increased vigilance against potential syn-eruption lahars and sediment-laden stream flows 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 said.
OTHER EARTHQUAKES
Phivolcs also reported earthquakes in La Castellana, Salvador Benedicto, Moises Padilla, and Murcia in Negros Occidental, and in Canlaon City, Negros Oriental, on Sunday.
The following earthquakes were reported on Sunday:
· Murcia: 2.3 magnitude at 3:34 a.m.
· Canlaon City: 1.7 magnitude at 6:04 a.m.
· La Castellana: 4.7 magnitude at 5:30 a.m.
· Canlaon City: 4.6 magnitude at 5:30 a.m.
· Salvador Benedicto: 1.4 magnitude at 5:48 a.m.
· Murcia: 2.0 magnitude at 5:48 a.m.
· Murcia: 1.4 magnitude at 6:04 a.m.
· Murcia: 1.2 magnitude at 6:06 a.m.
· Murcia: 2.0 magnitude at 6:08 a.m.
· Salvador Benedicto: 1.3 magnitude at 6:08 a.m.
· Moises Padilla: 2.6 magnitude at 2:59 p.m.
· La Castellana: 2.0 magnitude at 2:59 p.m.
There were no reports of damage to property or injuries, Sermeno said.*