Crater glow or banaag at Kanlaon Volcano observed with the naked eye on Sunday evening could be a precursor to an magmatic eruption, a Philippine Institute of Volcanology and Seismology (Phivolcs) official warned.
“We are not taking any chances because at Mayon Volcano before it erupted there was also a crater glow,” Ma. Antonia Bornas, Phivolcs Volcano Monitoring and Eruption Prediction Division chief, said on Monday, May 11.
Netizens on Sunday evening posted photos of a red glow at the crater of Kanlaon.
Phivolcs will be observing Kanlaon for the next few evenings to determine if the crater glow becomes sustained and intensifies, which would indicate that magma is close to or at the crater indicating increasing chances of magmatic unrest within days, Bornas said.
This would then necessitate the raising of the Alert Level at Kanlaon from 2 to 3, she said.
She said the observation so far is that the crater glow at Kanlaon is not sustained, sometimes it wanes and returns that could be superheated gas that is seeping through the volcano.
Donato Sermeno III, regional director of the Office of Civil Defense (OCD) in the Negros Island Region (NIR), said Alert Level 3 would mean evacuating residents within the six-kilometer expanded danger zone at Kanlaon.
This would mean 14,765 families with 73,765 residents in Canlaon City in Negros Oriental, and Bago City, La Carlota City, La Castellana, San Carlos City, Pontevedra and Moises Padilla in Negros Occidental would be affected by Alert Level 3, he said.
Based on their experience from the last Alert Level 3 raised on Dec. 9, 2024, the highest number of evacuees were 6,170 families with 18,890 individuals, he said.
The Regional Disaster Risk Reduction and Management Council – Negros Island Region (RDRRMC NIR), chaired by Sermeno III, convened a Pre-Disaster Risk Assessment–Scenario Building ) meeting Monday afternoon attended by various regional line agencies and local government units in the region.
Bornas advised the council to prepare for possible evacuation measures and the raising of alert status, Sermeno said.
The OCD will wait for further advice from Phivolcs, he said.
Sermeno said they will prioritize the evacuation of the elderly and children should the need arise.
Since Nov. 4, 2024 invisible emissions of superheated volcanic gas plumes from the Kanlaon Volcano summit crater had been occasionally detected at nighttime by infra-red and high-resolution camera monitoring by the Kanlaon Volcano Observatory (KVO), a Phivolcs advisory said.
Superheated gas activity has persisted this year, becoming more frequent since April 13. At around 7 p.m. on Sunday the KVO reported observing with the naked eye for the first time incandescence at the Kanlaon Volcano summit caused by superheated volcanic gas, followed by netizen reports of the same observations, it said.
While this is a new development, monitoring parameters have persisted in approximately the same level after Kanlaon’s last moderately explosive eruption on March 15, Phivolcs said.
Since then, seismicity remained at the steady rate of six volcano-tectonic earthquakes/day, while sulfur dioxide (SO2) gas emissions averaged 1,646 tons a day and have increased only slightly to 2,382 tons a day this past week, it added.
Ground deformation parameters have been non-steady but still indicate a sustained and slow-rate inflation of the volcano edifice since 2022, Phivolcs said.
The public is reminded that while Alert Level 2 prevails over Kanlaon, the alert status may step up to Alert Level 3 should magmatic eruption be forewarned by sustained and intensifying crater glow or banaag at the summit crater, Phivolcs said.
A magmatic eruption would generate life-threatening volcanic hazards such of pyroclastic density currents or PDCs, lava flows, ballistic projectiles, ashfall, rockfall and others, it said.
It is strongly recommended that communities within the 4-km radius Permanent Danger Zone or PDZ strictly remain evacuated and those within the PDC Hazard Zones be vigilant and ready for evacuation in case the chances of magmatic eruption increase, it added.
Local government and disaster risk reduction partners must prepare their response measures, paying special attention to the vulnerable members of the community including the elderly, those with medical conditions, expecting mothers and infants, Phivolcs said.
Increased vigilance against potential syn-eruption lahars and sediment-laden streamflow in channels draining the edifice is strongly advised should intense rains occur during eruptive unrest, it said.
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.*
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