Bulusan Volcano erupts, prompting alert level hike

An image of Bulusan Volcano erupting as captured by the Philippine Institute of Volcanology and Seismology at 4:52 a.m. on April 28, 2025.

MANILA, Philippines — Bulusan Volcano in Sorsogon erupted early Monday, prompting the escalation of its alert level, according to state volcanologists.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said the volcanic eruption began at 4:36 a.m. and ended by around 5 a.m., or lasting by around 24 minutes based on seismic and infrasound records in a later advisory.

Phivolcs said this event led to a bent plume that rose 4,500 meters above the crater before drifting west to southwest.

READ: Bulusan Volcano in Sorsogon now under normal status – Phivolcs

“Rumbling sounds were reported by local government officials approximately 15 minutes before the eruption and were recorded by infrasound sensors,” Phivolcs also noted.

Phivolcs then raised its Alert Level from zero (normal) to one (low-level unrest).

“Phivolcs is now raising the alert status of Bulusan from Alert Level 0 to Alert Level 1, which means that the volcano is currently in a state of low-level unrest with chances of phreatic eruptions succeeding this morning’s event,” the institute said in the same advisory.

Other factors, a sign to keep watch

Aside from the eruption, several factors led to the increase of the alert level.

State volcanologists said ashfall was reported in Barangays Cogon and Bolos in Irosin town; and Barangays Puting Sapa, Guruyan, Buraburan and Tulatula Sur in Juban town.

A pyroclastic density current, locally known as “uson,” descended the southwestern slopes and travelled within three kilometers from the summit vent, it said.

Also prior to the eruption, Phivolcs also noted that a total of 53 volcanic earthquakes were recorded over the 24-hour period — from 7 a.m. on Sunday to the same time Monday.

“The recorded phreatic eruption, or the explosion of a volcano accompanied by the emission of smoke this morning is a sign for all Sorsoganons, especially those living near the volcano, to be vigilant and follow any directives from our local government,” said Senate President Francis “Chiz” Escudero in a statement in Filipino.

Escudero, a former governor of Sorsogon, said the evacuation centers in the area as well as the disaster relief personnel are ready to assist.

The top Senate official also said he and the local government of Sorsogon are also in continuous coordination with the Office of Civil Defense and Department of Social Welfare and Development.

Poll contingency

Election officers (EOs) in Sorsogon were also given an instruction to formulate an “election-related contingency plan should there be an escalation of Mt. Bulusan activity,” Commission on Elections (Comelec) chairman George Erwin Garcia said on Monday.

To date, Garcia noted that the EOs of municipalities surrounding the foot of Mt. Bulusan reported no forced evacuation or use of any voting centers like schools as evacuation sites.

“The readiness of Sorsogon for the conduct of the elections has not been disrupted so far by the recent activity of Mt. Bulusan,” Garcia said in a statement.