ILOILO City – A phreatic or steam-driven eruption occurred at Kanlaon Volcano in Negros Island on Monday night.
The eruption began around 6:51 p.m., producing a 5,000-meter plume, and was ongoing as of this writing, according to the Department of Science and Technology – Philippine Institute of Volcanology and Seismology (DOST-PHIVOLCS).
DOST-PHIVOLCS raised the alert level of Kanlaon from Alert Level 1 (abnormal) to Alert Level 2 (increasing unrest) 8 p.m. on Monday. This means that there is current unrest driven by shallow magnetic processes that could eventually lead to further explosive eruptions of even precede hazardous magmatic eruption.
Last week, DOST-PHIVOLCS has issued a warning to local government units (LGUs) and the public regarding heightened seismic activity at Kanlaon Volcano in Negros Island.
The warning followed the recording of 24 volcano-tectonic (VT) earthquakes detected by the Kanlaon Volcano Network between 1:35 p.m. and 4:30 p.m. on May 26.
These earthquakes ranged from a magnitude of ML 0.8 to ML 2.3 and occurred at depths of zero to six kilometers beneath the western flank of the volcanic edifice.
Additionally, volcanic sulfur dioxide (SO2) gas emissions from the summit crater have been elevated, averaging 1,291 tonnes/day since January 1, 2024, with a spike to 2,003 tonnes/day on the day of the report.
Kanlaon is an active stratovolcano and the highest mountain on the island of Negros, as well as the highest peak in the Visayas, with an elevation of 2,465 meters (8,087 feet) above sea level. It straddles the provinces of Negros Occidental and Negros Oriental, approximately 30 km southeast of Bacolod, the capital and most populous city of Negros Occidental and whole island.
Ongoing measurements, including continuous GPS and electronic tilt data, have indicated a persistent inflation of the volcano that started between April and July 2023, alongside a longer-term inflation since March 2022.
DOST-PHIVOLCS noted that these monitoring parameters over the past months are consistent with shallow hydrothermal activity driven by the degassing of deeper magma. However, the current VT earthquake activity suggests shallow rock-fracturing, which could signal further unrest.
The agency has reminded the public that Kanlaon Volcano remains at Alert Level 1. Should the uptrend in monitoring parameters continue, there is a possibility that the alert status may be elevated to Alert Level 2 to indicate increasing unrest.
DOST-PHIVOLCS strongly advises the public and local government units to exercise vigilance and avoid entering the four-kilometer Permanent Danger Zone (PDZ) around the volcano, as there is an increased risk of sudden and hazardous phreatic eruptions.
The volcano is a favorite spot for mountain climbers and is the centerpiece of Mount Kanlaon Natural Park, a national park originally established on August 8, 1934.
DOST-PHIVOLCS also urged civil aviation authorities to caution pilots against flying near the volcano’s summit, as ejecta from any sudden eruption could pose a threat to aircraft.
DOST-PHIVOLCS is closely monitoring the situation and will provide updates on any new developments concerning Kanlaon Volcano./PN
