BULUSAN VOLCANO ADVISORY
22 October 2023

09:00 PM
 

This is a notice of seismic activity at Bulusan Volcano.
 

A total of eighty-seven (87) volcanic earthquakes were recorded by Bulusan Volcano Network (BVN) since 5AM of 14 October 2023. Of these, twenty-nine (29) were volcano-tectonic or VT earthquakes associated with rock fracturing processes occurring 1 to 8 kilometers beneath the southern and western sector of Bulusan Volcano. Degassing at the active summit crater and vents have been weak to moderate this week, while volcanic SO₂ gas emission last 19 October 2023 averaged near background values at 241 tonnes/day. Ground deformation data from electronic tilt monitoring indicate continued inflation of the general southern flank since February 2023. A notable increase of volcanic Carbon Dioxide (CO₂) concentrations from June to August 2023 and of spring temperature since February was detected in a monitored spring on the southwestern sector of the edifice. The above parameters indicate that hydrothermal activity driven by deep magma degassing may be occurring beneath the volcano and may lead to steam-driven eruptions at any of the summit vents.

Alert Level 0 (Normal) is maintained over Bulusan Volcano but there are increased chances of steam-driven or phreatic eruptions occurring at the crater or summit area. Local government units and the public, however, are reminded that entry into the 4-kilometer radius Permanent Danger Zone (PDZ) particularly near the vents on the south-southeastern slopes, should be avoided due to the possibility of sudden and hazardous steam-driven or phreatic eruption, rockfall and landslide. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft. Furthermore, people living within valleys and along river/stream channels should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall.

DOST-PHIVOLCS is closely monitoring Bulusan Volcano’s condition and any new development will be relayed to all concerned.

DOST-PHIVOLCS