The Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday raised Alert Level 1 over Mount Bulusan in Sorsogon after the volcano entered “a period of low-level unrest.”
Phivolcs said it had observed several volcanic earthquakes starting October 14. A total of 121 volcanic earthquakes have been recorded since then, the agency said
Deformation data gathered from electronic tilt and GPS monitoring “indicate inflation or swelling of the southern flank since February 2023 and of the northeastern flank since September 2023,” Phivolcs’ advisory read.
Phivolcs recorded a notable increase of volcanic carbon dioxide concentrations from June to August 2023.
“These parameters indicate that hydrothermal activity driven by deep-seated magma degassing may be occurring beneath the volcano and may lead to steam-driven eruptions at any of its summit vents,” it noted.
Entry to the four-kilometer radius permanent danger zone is prohibited.
The public should also be cautious in the two-kilometer extended danger zone.
Under Alert Level 1, there is increased possibility of “sudden and hazardous phreatic eruptions from the summit crater and/or lateral vents.”