PHIVOLCS reported that at 1851 on 3 June an explosive eruption at Kanlaon ejected incandescent material and produced a voluminous ash plume that rapidly rose 5 km above the vent and drifted W. Pyroclastic density currents generated from column collapses traveled 2-3 km down the S and SE flanks based on webcam views. The eruption was recorded by all 10 seismic stations, three infrasound stations, and webcams, and lasted six minutes based on the seismic data. Rumbling was heard in a La Castellana, La Carlota City, and Canlaon City. Coarse ashfall was reported in those same areas and additionally in Bago City. A sulfur odor was also reported in many neighborhoods in the cities of Bago, Bacolod, La Carlota, La Castellana, Murcia, and Canloan City. The Alert Level was raised to 2 (on a scale of 0-5) at 2000 and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone. The eruption was preceded by a M 3.5 volcano-tectonic earthquake at 1847. The gas (sulfur dioxide) portion of the plume rose 8-17 km, reaching the upper troposphere based on satellite data.

Abundant gas emissions followed the eruption and then waned by 0820 on 4 June. The emissions likely entrained ash that fell in minor amounts SW of the volcano. Sulfur dioxide emissions averaged 4,113 t/d, the highest gas flux recorded in 2024 and the second highest ever recorded at Kanlaon. According to the National Disaster Risk Reduction and Management Council (NDRRMC), a total of 1,888 people had evacuated to 11 evacuation shelters and a total of eight domestic flights and one international flight were cancelled.

Periodic swarms of volcano-tectonic earthquakes had been recorded since March 2020 and seismicity had been above background levels during the previous month. The report noted that sulfur dioxide emissions had been variable but increasing overall since May 2023 and anomalously high during the 2024, averaging 1,273 tonnes per day (t/d); background levels averaged less than 300 t/d.

Geological Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall.

Sources: The National Disaster Risk Reduction and Management Council (NDRRMC), Philippine Institute of Volcanology and Seismology (PHIVOLCS), Simon Carn