PHIVOLCS raises Bulusan Volcano’s alert status due to ‘low-level unrest’

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Wednesday raised Bulusan Volcano’s alert status due to “low level unrest.”

In an advisory, PHIVOLCS said it placed the alert status of the volcano in Sorsogon to Alert level 1 following the recorded 126 weak and shallow volcanic earthquakes since Tuesday morning.

“Most of these events occurred in the northwestern sector and the summit area of Bulusan and are attributed to rock-fracturing processes within the edifice,” it said.

BULUSAN VOLCANO BULLETIN
12 October 2022
3:00 P.M. #BulusanVolcanohttps://t.co/Fn0eqC6HgN pic.twitter.com/mObPdcEZ1H

— PHIVOLCS-DOST (@phivolcs_dost) October 12, 2022

PHIVOLCS said volcanic carbon dioxide concentrations measured monthly in springs on the southeastern sector of Bulusan have been increasing since July 2022, adding that the increasing spring temperature since April 2022 in monitored hotsprings on the southwestern sector.

The agency said sulfurous odor was also reported by residents in Sitio Talistison, Brgy. Mapaso, Irosin and Brgy. San Roque, Bulusan on October 10 to 11.

On ground deformation, PHIVOLCS said a pronounced and ongoing inflationary trend that began in September 2022 was also detected by most of the electronic tilt stations on the southwestern and southern slopes.

It said that the current inflation cycle signifies ongoing pressurization of the shallow hydrothermal system.

PHIVOLCS then warned that entry into the four kilometer radius Permanent Danger Zone (PDZ) is strictly prohibited and vigilance in the two kilometer Extended Danger Zone (ED) on the southeast sector must be exercised “due to the increased possibilities of sudden and hazardous phreatic eruptions.”

The agency also advised civil aviation authorities and pilots to 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/stream channels especially on the southeast, southwest and northwest sector of the edifice should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur,” it added.

PHIVOLCS said it is closely monitoring the volcano’s condition and new developments will be reported. — BM, GMA News