PHIVOLCS reported that during 19-20 December there were 412 volcanic earthquakes detected at Kanlaon. A low-energy, explosion-type earthquake was detected at 0233 on 21 December associated with gas emissions from the summit area. Later in the day steam plumes rose 400 m and drifted NE. The number of daily volcanic earthquakes increased to 957 the next day and then decreased to less than 20 per day during 22-23 December; the daily count increased to 382 and 776 events on 24 and 25 December, respectively, and then decreased to 82 on 26 December. White plumes rose 300 m and drifted NE, NW, and SW on 21 December, and 700 m on 26 December; weather clouds prevented views on the other days. The Alert Level remained at 2 (on a scale of 0-5).

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)