PHIVOLCS reported that between 24 June and 18 August the seismic network at Kanlaon detected 244 volcanic earthquakes. The report stated that the increased seismic activity could be followed by phreatic explosions at the summit crater, despite the absence of visible degassing or steaming from the active vent during 2017. The Alert Level was raised to 1 (on a scale of 0-5), and the public was warned to not enter the 4-km-radius Permanent Danger Zone (PDZ).

Geological Summary. Kanlaon volcano (also spelled Canlaon) forms the highest point on the island of Negros, Philippines. 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)