PHIVOLCS monitors 'increased seismic activity' at Bulusan Volcano

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Tuesday reported an ‘’increased seismic activity’’ at Bulusan Volcano in Sorsogon as it reiterated its warning to the public that entry into the four-kilometer-radius danger zone is prohibited.

The agency has recorded 116 volcanic earthquakes since 9 p.m. of December 29, 2023, and the swelling of the southwestern and southeastern slopes since February 2023.

‘’In contrast, degassing activity from the summit crater and active vents has been very weak to moderate when the volcano summit has been visible. Nonetheless, increased seismic activity and pressurization of the volcano edifice may indicate that hydrothermal processes may be occurring beneath the volcano and may lead to steam-driven eruptions at any of the summit vents,’’ PHIVOLCS said in its latest bulletin.

Alert Level 1 remains hoisted over Bulusan Volcano. This means the volcano ‘’is currently at low-level unrest with increased chances of steam-driven or phreatic eruptions,’’ PHIVOLCS said.

‘’Local government units and the public are reminded that entry into the 4-kilometer radius Permanent Danger Zone (PDZ) should be prohibited and that vigilance in the 2-kilometer Extended Danger Zone (EDZ) on the southeast sector must be exercised due to the possibilities of sudden and hazardous phreatic eruptions,’’ it said.

Civil aviation authorities were also asked to advise pilots to avoid flying close to the volcano’s summit, as ash from any sudden phreatic eruption can be hazardous to aircraft.

It also urged people living within valleys and along river or stream channels to be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall occurring simultaneously with a phreatic eruption. — VBL, GMA Integrated News