PHIVOLCS reported that an approximately 10-minute-long, low-energy phreatic eruption at Kanlaon began at 0947 on 9 December. A plume of voluminous steam and dark ash rose 3-4 km above the summit vent. The event was heard as far away as La Castellana, Negros Occidental. Minor amounts of ash fell in Sitio Guintubdan, and barangays Ara-al, Sag-ang, and Ilihan. The eruption was preceded by the resumption of degassing at the summit crater at 0634, detectable as continuous low-energy tremor during periods when the summit was not visible; degassing was last observed September 2016. The Alert Level remained at 2 (on a scale of 0-5).

Geological Summary. Kanlaon volcano (also spelled Canlaon), the most active of the central Philippines, forms the highest point on the island of Negros. The massive andesitic stratovolcano is dotted 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, historically active vent, Lugud crater, to the south. Historical eruptions, recorded since 1866, have typically consisted of phreatic explosions of small-to-moderate size that produce minor ashfalls near the volcano.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)