SORSOGON, Philippines – A phreatic or steam-driven eruption rocked the summit of Bulusan Volcano at 4:36 AM on 28 April 2025, lasting 24 minutes. According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), all 11 monitoring stations of the Bulusan Volcano Network (BVN) recorded the eruption, which generated a towering plume that reached approximately 4,500 meters before drifting westward.
Communities in the western Sorsogon Peninsula, including Irosin, Juban, and Magallanes, reported light ashfall ranging from trace amounts to a thickness of 1 millimeter. Affected barangays include Cogon, Tinampo, Omagom, Gulang-Gulang, and Bolos in Irosin; Puting Sapa, Buraburan, and Guruyan in Juban; and Tula-tula Sur, Caditaan, Cadandanan, Siuton, and Salvacion in Magallanes.
PHIVOLCS also noted ash clouds from small-volume pyroclastic density currents (PDCs) descending the volcano’s southwestern slopes. These PDCs are highly dangerous mixtures of hot gases, ash, and volcanic debris. Residents in several barangays of Irosin and Juban reported rumbling sounds and sulfuric fumes, further indicating the eruption’s force and reach.
In the 24 hours leading up to the eruption, 53 volcanic earthquakes were recorded. A strong tremor and infrasound signal at 3:54 AM—lasting 29 minutes—preceded the eruption, likely indicating shallow hydrothermal activity and vent opening. Following the eruption, active degassing has continued, with 86 volcanic earthquakes logged by 8:00 PM, showing that unrest beneath the volcano persists.
PHIVOLCS has raised Alert Level 1 over Bulusan Volcano, signifying low-level unrest. Authorities strongly advise the public to avoid the 4-kilometer Permanent Danger Zone (PDZ) and remain vigilant within the 2-kilometer Extended Danger Zone (EDZ) due to risks of further phreatic eruptions, ashfall, ballistic projectiles, and PDCs.
Residents in ashfall areas are urged to wear masks or damp cloths to avoid inhalation, especially the elderly, children, and those with respiratory issues. Civil aviation authorities are warned to avoid flying near the summit due to the risk posed by volcanic ash. Additionally, communities near river channels should prepare for possible lahars if heavy rains occur.
Stay alert for further updates from PHIVOLCS.