Bulusan Volcano in Sorsogon remained restive as degassing from its summit vents continued on Monday, June 13, said the Philippine Institute of Volcanology and Seismology (Phivolcs).

“Steam-laden plumes have been generated with periods of profuse volume and sporadic ashing that began at 4:30 a.m. today (June 13),” Phivolcs said in its 5 p.m. update.

At least five episodes of emissions of gray ash plume about 400- to 750-meter-high from the Blackbird Crater and profuse steaming from the summit vents were observed from the IP cameras of the Bulusan Volcano Network (BVN).

“These events registered very weakly or not at all in the seismic record and not at all in the infrasound record of the BVN,” Phivolcs said.

“Much of the ash was dispersed to the northwest of the summit, but no ashfall on population centers has been additionally reported,” it added.

Phivolcs said light ashfall was observed in Catanusan, Juban, Sorsogon and on the upper northwest slopes of Bulusan Volcano at around 9 a.m.

Phivolcs said the active volcano remains under Alert Level 1, which means it is still in a state of hydrothermal unrest.

Bulusan Volcano’s status has been raised from Level 0 to Level 1, following a phreatic eruption on June 5. It had another phreatic eruption on June 12.

Phivolcs reminded the public that entry into the four-kilometer permanent danger zone is strictly prohibited because of possible sudden steam-driven or phreatic eruptions.

Meanwhile, the public is advised to remain vigilant when entering the two-kilometer extended danger zone, which is in the southeast sector of Bulusan Volcano.

Furthermore, people living within valleys and along river/stream channels especially on the southeast, southwest and northwest sector of the edifice were advised to be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should another phreatic eruption occurs.

Bulusan Volcano also had phreatic eruptions on June 5 and 12.