The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 16-23 December. The seismic network recorded 1-7 daily volcanic earthquakes. Gas-and-steam emissions of variable densities rose as high as 100 m above the crater rim and drifted NW, W, and SW; weather clouds obscured views on 18 December. Daily sulfur dioxide emissions ranged from 1,787 to 2,763 tonnes per day. Diffuse ash emissions rose 300 m above the summit and drifted NW during 0901-0929 and 1029-1107 on 22 December. Later that day a period of ash emissions began at 1605 and persisted for about two hours, sending plumes as high as 900 m above the summit that drifted NW. By the end of the day there had been four periods of ash emissions. The Alert Level remained at 2 (on a scale of 0-5); the public was warned to stay out of the 4-km-radius Permanent Danger Zone (PDZ) and pilots were advised to avoid flying close to the summit.

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.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)