Volcanic activity at Kanlaon is continuously monitored by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), the government's bureau that monitors the volcanoes and earthquakes in the nation, although unlike Mayon and Pinatubo, the volcano has never been studied in-depth and its age is not yet accurately calculated.
One of the rescued Belgians, Caroline Verlinde, said she and her group were about to leave a site near the crater rim when suddenly the volcano ejected ash, stones and hot gas.