PHIVOLCS: Increased seismic activity at Bulusan Volcano

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that a total of 91 volcano-tectonic earthquakes at Bulusan Volcano early Tuesday morning.

The earthquakes are associated with rock fracturing at 2 to 4 kilometers in depth beneath the southwestern flanks at 1:30 a.m. on January 23, 2024.

"The southwestern as well as southeastern flanks of Bulusan Volcano have been inflated since February 2023 based on ground deformation data from continuous GPS and electronic tilt monitoring," said PHIVOLCS.

However, degassing activity was observed from the summit crater, when it was visible, and active vents has been very weak to moderate.

The agency explained that "increase 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."

Bulusan Volcano remains under Alert Level 1, PHIVOLCS said, which means that it is at "low level unrest with increased chances of steam-driven or phreatic eruptions."

Local government units and the general public are also reminded to observe restrictions imposed in the area.

Entry into the 4-kilometer radius Permanent Danger Zone (PDZ) should be prohibited, the public should be vigilant in the 2-kilometer Extended Danger Zone (EDZ) on the southeast sector due to the possibility of sudden and hazardous phreatic eruptions.

"Civil aviation authorities must also advise pilots to avoid flying close to the volcano's summit as ash from sudden phreatic eruption can be hazardous to aircraft," said PHIVOLCS.

For the people living within valleys and along river and stream channels should be vigilant and watch for sediment-laden stream flows and lahars when heavy rainfall occurs simultaneous with phreatic eruption. — BAP, GMA Integrated News