Mount Bulusan in Sorsogon underwent a phreatic eruption early Monday morning, causing ashfall in nearby towns.

Information from the Philippine Institute of Volcanology and Seismology (PHIVOLCS) disclosed that the volcanic activity started at 4:36 a.m. and lasted until 5:00 a.m., generating a bent plume reaching up to 4.5 kilometers from the volcano’s summit, which drifted in a west-southwest direction.

Due to the volcano’s unrest, state seismologists placed Mount Bulusan under Alert Level 1, indicating a “slight increase in volcanic earthquake and steam activity,” as well as slight inflation within the volcano’s edifice.

Inflation of the volcano’s edifice signals continuous accumulation of pressurized magma beneath the surface.

PHIVOLCS is currently monitoring four active volcanoes: Bulusan, Mayon, and Taal, all under Alert Level 1, and Kanlaon, which remains under Alert Level 3.

Ashfall was recorded in barangays within the towns of Irosin, Magallanes, and Juban.

On 21 April, state seismologists reported an increase in volcanic activity at Mount Bulusan, citing a rise in weak and shallow volcano-tectonic earthquakes within the edifice.

The public is prohibited from entering the four-kilometer radius of the Permanent Danger Zone, as well as the two-kilometer Extended Danger Zone in the volcano’s southeastern sector, due to the potential effects of pyroclastic density currents (PDCs).

The Sorsogon Provincial Information Office reported that the provincial government has pre-positioned 240 food packs for the municipality of Juban and 400 food packs for the municipality of Irosin.

Department of Social Welfare and Development (DSWD) Secretary Rex Gatchalian is set to visit Sorsogon on Tuesday. An additional 180,000 food packs have been pre-positioned at DSWD Field Office 5 in the Bicol Region.

Officials from the Bureau of Fire Protection, Philippine National Police, and Sorsogon Provincial Disaster Risk Reduction and Management Council (SPDRRMC) are conducting clearing operations along the city’s main roads to remove ashfall from the eruption.