PHIVOLCS issued a special notice for Kanlaon on 21 January, noting that a total of 18 volcanic earthquakes were recorded in the past day. Four of those events were classified as shallow “tornillo” signals indicating gas movement along shallow fractures in the upper part of the volcano. Ground deformation data from continuous GPS and tilt measurements indicated slight inflation of the volcano since mid-October 2021. The seismic activity and ground deformation was likely caused by shallow hydrothermal processes and could generate phreatic events. The Alert Level remained at 1 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone.

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)