By Ma. Cristina Arayata, Mary Judaline Partlow and Nanette Guadalquiver

ERUPTION. A 5,000-meter high plume lights up the dark sky as Mt. Kanlaon in Negros Island erupted after sundown on Monday (June 3, 2024). The Phivolcs has hoisted Alert Level 2 over Negros while Canlaon City Mayor Jose Cardenas has ordered the evacuation of four barangays in the danger zone. (Photo from the Facebook page of Dumaguete Bishop Julito Cortes)

BACOLOD CITY – Mt.  Kanlaon, an active volcano in Negros Island, erupted for six minutes Monday night, producing a 5,000-meter plume, the Department of Science and Technology-Philippine Institute of Volcanology and Seismology (DOST-Phivolcs) said in a report.

The steam-driven or phreatic explosion occurred at the summit vent at 6:51 p.m.

As of 8 p.m., Phivolcs raised Mt. Kanlaon’s alert level from  Alert Level 1 (abnormal) to Alert Level 2 (increasing unrest), which  means “there is current unrest driven by shallow magmatic processes that could eventually lead to further explosive eruptions or even precede hazardous magmatic eruption.”

Phivolcs said the “eruption produced a voluminous and incandescent plume that rapidly rose to 5,000 meters above the vent and probable short pyroclastic density currents approximately two to three kilometers down the southern and southeastern slopes.”

The eruption was preceded by a relatively strong volcano-tectonic earthquake, the report further said.

According to Phivolcs, there have been reports of coarse ashfall and sulfurous odors in communities on the western slopes of the volcano.

“DOST- Phivolcs maintains close monitoring of Kanlaon Volcano, and any new development will be communicated to all concerned stakeholders,” it added.

In Negros Occidental, local government units near Mt. Kanlaon are those of La Castellana town and La Carlota City, which have communities at the foot of the volcano.

Others with villages near the volcano include the cities of San Carlos and Bago and the towns of Moises Padilla and Murcia.

In an advisory, the La Castellana Municipal Disaster Risk Reduction Office said it is preparing for possible escalation of the alert level of Mt. Kanlaon.

It also advised residents to wear face masks, especially those who have respiratory illnesses.

Evacuation ordered

In Negros Oriental, Mayor Jose Chubasco Cardenas of Canlaon City ordered the evacuation of residents in four barangays following the eruption.

Residents of Barangays Masulog, Pula, Lumapao and Malaiba as well as their livestock, have to be evacuated immediately since these areas are in the permanent danger zone, Cardenas said in an interview with the Philippine News Agency.

The mayor added that he has mobilized all resources to ensure the safety of the people following the eruption of the volcano.

“I already contacted the OPAV (Office of the Presidential Assistant for the Visayas), the regional DSWD (Department of Social Welfare and Development, the provincial DSWD, the provincial and local Disaster Risk Reduction and Management Offices, just in case necessary assistance has to be given,” Cardenas said.

The mayor also thanked Negros Oriental Governor Manuel Sagarbarria who promised to provide assistance and resources.

Cardenas has mobilized all trucks and asked for assistance from officials of neighboring municipalities and cities through the governor.

Possible magmatic eruption

Meanwhile, Negros Island folks are told to prepare face masks following the eruption.

“That is an explosive eruption and could progress into hazardous magmatic eruption,” Phivolcs Director Teresito Bacolcol told the Philippine News Agency.

“Explosive volcanic eruptions occur when volcanic gas expands quickly. When the pressure is too high, gases are released suddenly, causing powerful explosion that blasts out ash, gas and lava,” Bacolcol explained.

He said ash fall is included in the plume, thus the public needs to prepare face masks.

“We just don’t know yet the areas where the ash fall could reach as that would depend on the prevailing wind directions. People have to wear face masks when there are ash falls,” he said.

Bacolcol also said they edited the Phivolcs’ eruption notification from “phreatic” to “explosive”.

“For now, we cannot ascertain if this is a phreatic eruption (driven by hot materials coming into contact with water, producing steam) or a combination of phreatic and magmatic eruption (driven by magma coming from the volcano),” Bacolcol admitted.

“Phreatic eruptions can also be explosive eruptions. By using the term ‘explosive eruption’, we are describing how strong the eruption is,” he added.

Entering the four-km permanent danger zone is strictly prohibited due to increased chances of sudden and hazardous phreatic eruption.

Aviation authorities are advised to tell pilots to avoid flying close to the volcano’s summit as ejecta from any sudden phreatic eruption could be hazardous.   (PNA)