Philippines: Ash blankets towns as volcano erupts, pilots warned to avoid flying close to Mt Bulusan

Manila: A pre-dawn eruption of Bulusan Volcano on Monday has kicked off a massive ashfall that blanketted several towns in Sorsogon province.

Volcanologists reported a steam-driven plume from the volcanic crater soaring 4,500 metres above the crater, drifting west to southwest.

Aviation authorities warned pilots against flying near Bulusan’s summit, as volcanic ash could pose serious hazards to aircraft.

The Philippine Institute of Volcanology and Seismology (Phivolcs) reported that the 24-minute eruption began at 4:36 am.

Steam-driven explosions usually occur when water interacts with magma or hot rocks. 

Authorities raised the alert status from Level 0 (normal) to Level 1 (low-level unrest).

Ashfall

Ashfall was reported in Barangays Cogon and Bolos in Irosin, and Barangays Puting Sapa, Guruyan, Buraburan in Juban.

Ashfall was also reported in several villages in Magallanes town, including Busay, Siuton, Ginangra, Magsaysay, Lapinig, Biton, Salvacion.

Rumbling

Volcanologists reported that a pyroclastic density current (PDC) flowed down Bulusan’s southwestern slopes, travelling up to 3 kilometers from the summit vent.

Local officials reported rumbling sounds about 15 minutes before the eruption, which were later confirmed by infrasound sensors.

In the 24 hours preceding the eruption, the agency recorded 53 volcanic earthquakes.

Phivolcs warned the public against entering the four-kilometer Permanent Danger Zone (PDZ) around the volcano and urged vigilance within the two-kilometer Extended Danger Zone (EDZ) in the southeast sector due to possible hazards such as PDCs, ashfall, rockfall, ballistic projectiles, and landslides.

Protective gear

Residents affected by ashfall are advised to wear protective masks or use wet cloths to avoid inhaling volcanic ash.

Those living along valleys and river channels, particularly on the southeast, southwest, and northwest sectors, should remain alert for potential sediment-laden flows and lahars, especially during heavy rainfall.

The latest Phivolcs bulletin issued at 7AM on Monday reported that Bulusan Volcano's seismic monitoring network recorded 98 volcanic earthquakes since April 12, 2025.

These earthquakes are associated with shallow hydrothermal or magmatic activity beneath the volcano.