Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Kanlaon during 17-24 September, characterized by increased seismicity and sulfur dioxide emissions. The seismic network recorded five volcanic earthquakes during 17-18 September and 15-55 daily volcanic earthquakes during the rest of the week. Weather clouds obscured views of the summit during 17-19 September. Voluminous gas-and-steam emissions rose 300-800 m above the summit and drifted in multiple directions during 20-23 September. Sulfur dioxide emissions were recorded daily and continued to be high, averaging 5,362-10,449 tonnes/day. According to a Disaster Response Operations Monitoring and Information Center (DROMIC) report there were a total of 3,905 people in evacuation centers as of 22 September. The Alert Level remained at 2 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone and warned pilots not to fly close to the volcano.

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: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Disaster Response Operations Monitoring and Information Center (DROMIC)