Mount Bulusan: Phivolcs detects 71 ‘rock fracture-linked’ quakes

Mount Bulusan in Sorsogon (File picture)

MANILA, Philippines — State volcanologists detected increased earthquakes at Mount Bulusan in Sorsogon on Thursday.

As of 5:00 a.m., the Philippine Institute of Volcanology and Seismology (Phivolcs) recorded 71 volcanic and tectonic earthquakes in Bulusan volcano “associated with rock fracturing.”

The magnitude of the earthquakes ranged from 0.3 to 2.2.

The tremors occurred between one to six kilometers beneath the southern flank of the volcano’s edifice.

“The seismic parameters indicate shallow hydrothermal activity is underway and may lead to steam-driven or phreatic eruption,” Phivolcs said in its 10 a.m. advisory.

Despite this activity, Phivolcs said Bulusan volcano remains under alert level 1, meaning it is now at a low level of unrest.

Nevertheless, state seismologists reminded the public to remain vigilant.

Entry into the four-kilometer radius of the Permanent Danger Zone is prohibited.

Residents within the two-kilometer Extended Danger Zone on the southeast sector of the volcano should watch out for possible “sudden and hazardous phreatic eruptions,” according to Phivolcs.

Pilots should also avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft.

People living within valleys and along river or stream channels must also be vigilant against sediment-laden stream flows and lahars.

The movement of these pyroclastic materials may happen during heavy and prolonged rainfall, especially after a phreatic eruption.