Fewer ground tremors are being recorded in the vicinity of Kanlaon Volcano in Negros Occidental but steam emission at the volcano’s vent continues to be observed by the Philippine Institute of Volcanology and Seismology (Phivolcs).
Kanlaon Volcano’s monitoring network recorded 10 volcanic earthquakes during the 24-hour observation period from Aug. 1 to Aug. 2 but the recorded earthquakes were too small to be felt.
A moderate emission of white steam-laden plumes that rose 600 meters before drifting northwest was also observed from the volcano’s summit.
Phivolcs also noted that the sulfur dioxide (SO2) emission was measured at an average of 723 tons per day.
The presence of significant sulfur dioxide from a volcano could indicate that magma is still getting closer to the surface.
According to Phivolcs, ground deformation data from continuous GPS measurements indicate a slight deflation of the lower and mid slopes since January this year.
“However, short-term electronic tilt monitoring on the southeastern flanks recorded inflation on the lower to mid slopes that began on June 21, 2020,” it said.
Phivolcs said that these parameters indicate that hydrothermal or magmatic processes are still occurring beneath the Kanlaon Volcano.
Kanlaon Volcano has been under Alert Level 1, the lowest on a five-tier scale, since March 11, 2020. It means the active volcano is at an abnormal condition and has entered a period of unrest.
Phivolcs warned the public that entry into the four-kilometer permanent danger zone is strictly prohibited due to possible sudden and hazardous steam-driven or phreatic eruptions.
Civil aviation authorities were asked to advise pilots to avoid flying close to the volcano’s summit as airborne ash and ballistic fragments from sudden phreatic eruption may pose hazards to aircraft.