Kanlaon Volcano has calmed down* Romeo Subaldo photo
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Tuesday, July 29, lowered Kanlaon Volcano’s status from Alert Level 3 to 2 or from high level volcanic unrest to moderate unrest.
“This is good news,” Governor Eugenio Jose Lacson said.
The change allows about 3,860 residents who have been living in evacuation centers since December to return home, Donato Sermeno III, director of the Office of Civil Defense Negros Island Region, said.
PHIVOLCS, in an advisory issued at 6:30 p.m. Tuesday, said under Alert Level 2, communities within the 4-kilometer Permanent Danger Zone (PDZ) should remain evacuated.
The previous PHIVOLCS recommendation covered a 6-kilometer extended danger zone.
This means only 45 families from Canlaon City and 36 from La Castellana who live within the PDZ cannot return to their homes, Sermeno said.
Bago City is permanently relocating 22 families from geologically isolated and disadvantaged areas outside the 4-kilometer PDZ, so they will also not be going home, he said.
Currently, about 1,281 families with 4,160 individuals are in evacuation centers across La Castellana, La Carlota City and Bago City in Negros Occidental, and Canlaon City in Negros Oriental, Sermeno said.
Of those in evacuation centers only the 103 families with about 300 individuals from the 4-kilometer PDZ and geologically isolated and disadvantaged areas cannot go home, Sermeno said.
La Castellana Mayor Añejo Nicor welcomed the lowered alert level, noting that residents have been in evacuation centers for over six months.
He is waiting for clearance from the OCD for La Castellana’s evacuees to go home, he said, pointing out that they still have about 2,000 residents in evacuation centers.
The mayor said he continues to pray for the volcano to remain calm.
REASONS FOR DOWNGRADE
PHIVOLCS said among the reasons for the alert level downgrade are:
• Less frequent volcanic earthquake activity since the last eruptive activity on May 13;
• Decreased volcanic gas emitted by subsurface magma;
• Improved ground deformation cycles; and
• Cessation of ash emissions from the summit crater after June 5, which had begun in October 2024. Activity at the crater has transitioned to quiet degassing of steam-dominated plumes.
PHIVOLCS noted a short-term deflation of Kanlaon’s edifice from late June to early July, suggesting a pause in magma intrusion or depressurization due to reduced volcanic gas in the system.
A total of 306 ash emission events had been recorded at Kanlaon since Oct. 19, 2024, along with five explosive eruptions between June 3 and May 13, Phivolcs said.
DANGER STILL EXIST
While Alert Level 2 indicates decreased unrest, PHIVOLCS emphasized it does not mean unrest has ceased or that the threat of an eruption has disappeared, as magma has already intruded deep beneath the edifice.
Lingering chances of short-lived explosive eruptions and sudden steam-driven or phreatic explosions remain, which can generate life-threatening volcanic hazards such as pyroclastic density currents (PDCs), ballistic projectiles, rockfalls, and lethal expulsions of volcanic gas, it said.
Should monitored parameters show an uptrend, the Alert Level may be raised back to Alert Level 3, Phivolcs added.
At such time people residing within areas at high risk to PDCs who have returned home after the step-down to Alert Level 2 must be prepared for a quick and organized evacuation, it said.
Phivolcs also said a persistent downtrend of parameters over a sufficient observation period could also lead to a further lowering of Kanlaon’s level to one.
VIGILANCE NEEDED
Local government units must continue preparing communities within PDC hazard zones for potential evacuation if unrest re-escalates, it said.
Increased vigilance against lahars and sediment-laden streamflows in channels draining the volcanic slopes is also crucial, especially if eruptive unrest resumes during heavy rainfall, Phivolcs said.
Civil aviation authorities are advised to caution pilots against flying close to the volcano’s summit, as ash from any sudden eruption can be hazardous to aircraft, it added.*