MANILA, Philippines (Updated 1:18 p.m.) — State volcanologists on Sunday morning raised the status of Bulusan Volcano in Sorsogon to Alert Level 1, indicating a low level of unrest.
This is to notify the public and concerned authorities of an ongoing phreatic eruption at Bulusan Volcano. Details to follow.
— PHIVOLCS-DOST (@phivolcs_dost) June 5, 2022
This comes after a phreatic eruption was recorded in Bulusan Volcano at 10:37 a.m., which lasted around 17 minutes.
"The event was poorly visible through cloud cover over the edifice although a steam-rich grey plume at least 1 kilometer tall was observed from Juban, Sorsogon and was subsequently observed to drift west," Phivolcs said in a bulletin.
Ashfall has been reported in the municipalities of Juban and Casiguran in Sorsogon.
In the past 24-hour before eruption, 77 volcanic earthquakes have been recorded.
Phivolcs said its electronic tilt monitoring documented a sudden but isolated inflation of the southeast lower slopes only since April 2022.
It added: "These parameters indicate that volcanic processes are underway beneath the edifice that are likely caused by shallow hydrothermal activity."
The public is warned against entry into the four-kilometer radius permanent danger zone and is urged to exercise vigilance in the extended danger zone due to the increased 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 any sudden phreatic eruption can be hazardous to aircraft," Phivolcs said.
Residents within valleys and along rivers or 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.
Bulusan, a stratovolcano, is considered one of the most active volcanoes in the country.