Kanlaon Volcano sulfur dioxide reaches record high on June 28

'This is the highest emission from the volcano recorded since instrumental gas monitoring began,' says Phivolcs

MANILA, Philippines – The sulfur dioxide (SO2) emission from Negros Island’s Kanlaon Volcano surged to a record high of 5,397 tons per day on Friday, June 28.

“This is the highest emission from the volcano recorded since instrumental gas monitoring began,” said the Philippine Institute of Volcanology and Seismology (Phivolcs) in an advisory on Friday evening.

Kanlaon has been under Alert Level 2 since June 3, following a “moderately explosive eruption” that forced residents living near the volcano to evacuate, caused ashfall, triggered lahar, and even killed thousands of farm animals.

Alert Level 2 means “there is current unrest driven by shallow magmatic processes” that may lead to further explosive eruptions, “or even precede [a] hazardous magmatic eruption,” Phivolcs warned.

The agency noted that Kanlaon’s SO2 emission has averaged 1,897 tons per day in 2024, but emission since the June 3 eruption “has been particularly elevated at a current average of 3,175 tons per day.” These levels are much higher than the typical emission of less than 300 tons per day when the volcano is not in a state of unrest.

State volcanologists have also recorded an average of 10 volcanic earthquakes per day since the eruption, while Kanlaon’s edifice has been inflated or swollen since March 2022, “indicating slow but sustained pressurization within the volcano.”

Phivolcs reminded the public not to enter the 4-kilometer-radius permanent danger zone (PDZ) surrounding Kanlaon “to minimize risks from volcanic hazards such as pyroclastic density currents, ballistic projectiles, rockfall, and others.” Ashfall and lahar flows remain possible as well.

The agency earlier said barangays with areas within Kanlaon’s PDZ are:

• Ara-al and Yubo in La Carlota City, Negros Occidental
• Sag-ang, Mansalanao, Cabagnaan, and Biaknabato in La Castellana, Negros Occidental
• Minoyan in Murcia, Negros Occidental
• Codcod in San Carlos City, Negros Occidental
• Masulog, Pula, and Lumapao in Canlaon City, Negros Oriental

Kanlaon, which straddles the provinces of Negros Occidental and Negros Oriental, is one of the Philippines’ two dozen active volcanoes. – Rappler.com