After weeks of relative quiet, Bulusan Volcano in Sorsogon is once again showing signs of unrest — prompting authorities to raise its alert status and remind nearby communities to stay vigilant.
The Philippine Institute of Volcanology and Seismology (Phivolcs) has placed Bulusan under Alert Level 1 following a surge in volcanic earthquakes recorded over the past week.
Since 15 March, Phivolcs has logged 475 weak volcano-tectonic earthquakes beneath the volcano — an indication of ongoing internal activity that could lead to further unrest.
Subtle changes have also been observed on the volcano’s surface, including slight ground deformation. On 17 March, Bulusan emitted 91 tons of sulfur dioxide, signaling continued degassing linked to the seismic activity.
While Alert Level 1 does not indicate an imminent eruption, it reflects low-level unrest that warrants caution.
Entry into the four-kilometer permanent danger zone has been strictly prohibited, with Phivolcs also warning residents within the additional two-kilometer extended danger zone of possible hazards, including sudden pyroclastic density currents in the event of steam-driven explosions.
Communities on the western flank of the volcano have been advised to remain alert for possible ashfall, while those in southwestern valleys are urged to closely monitor river channels for sediment-laden flows that may occur during periods of unrest or heavy rainfall.
The latest development marks a shift from just over a month ago, when Bulusan was downgraded to Alert Level 0 on 6 February after activity had subsided and no magmatic eruption was seen in the near term.
Its most recent eruption occurred in April 2025, when a phreatic — or steam-driven — event sent ash into the air, a reminder of how quickly conditions can change.
Bulusan now shares Alert Level 1 status with Taal Volcano in Batangas, which continues to emit significant volcanic gas, releasing 698 tons of sulfur dioxide on 21 March.
For now, authorities stress there is no cause for panic — but the renewed activity serves as a clear signal: Bulusan is awake, and it’s worth watching.