Mount Bulusan has not stopped shaking. As of late May 2026, the 1,565-meter stratovolcano in Sorsogon province remains at Alert Level 3, the second-highest tier on the Philippine Institute of Volcanology and Seismology (PHIVOLCS) scale, with white steam plumes climbing as high as 200 meters above the crater rim and a five-kilometer exclusion zone keeping thousands of residents away from farms, trails, and homes on the volcano’s slopes.
The situation has held in this tense middle ground for weeks: too active to relax restrictions, not explosive enough to trigger the mass evacuations that a Level 4 or Level 5 declaration would demand. For the farming communities of Irosin, Juban, and Bulusan town, the wait is grinding.
What PHIVOLCS is reporting
PHIVOLCS raised Bulusan’s status after detecting a surge in volcanic earthquakes beneath the edifice earlier in 2026. Subsequent escalations brought the alert to Level 3, which the agency defines as a state of relatively high unrest with a real possibility of hazardous eruption. In Bulusan’s case, the primary threat is phreatic: superheated groundwater flashing to steam and blasting rock, ash, and debris from the crater with little advance warning.
The agency has explicitly warned of possible steam-driven explosions and reiterated that no one should enter the permanent danger zone. Phreatic blasts are among the most treacherous volcanic hazards precisely because they can happen suddenly. Unlike magmatic eruptions, which often telegraph their arrival through days of intensifying tremor and ground swelling, a steam explosion can go from quiet venting to a lethal barrage of ballistic rocks in minutes.
The 200-meter plume height, a metric volcanologists use to gauge hydrothermal pressure and degassing intensity, appears in mid-May 2026 reporting compiled by the Smithsonian Institution’s Global Volcanism Program, which cross-references PHIVOLCS bulletins. The consistency between the Philippine agency’s releases and the Smithsonian’s independent record confirms that the alert level, plume descriptions, and danger-zone boundaries are aligned and current.
Residents, local officials, and disaster coordinators can check the latest Bulusan Volcano Bulletin through the government’s own GeoRisk volcano dashboard, which feeds directly into the planning tools that provincial and municipal governments use to coordinate evacuations and relief.
What the data does not yet show
Several important gaps remain in the public record. PHIVOLCS has not released daily bulletin PDFs with raw seismic counts corresponding to the dates of the reported 200-meter plumes. Without those earthquake tallies, outside analysts cannot compare the current unrest to historical thresholds that preceded larger eruptions at Bulusan or at similar Philippine stratovolcanoes.
Real-time instrumental readings, including Real-time Seismic Amplitude Measurement (RSAM) data and GPS-based ground deformation figures, have appeared only in secondary summaries rather than as direct data exports. Those numbers would reveal whether the magma or hydrothermal system beneath Bulusan is inflating, a signal that would raise the probability of escalation beyond phreatic activity. Their absence from public-facing platforms means scientists outside PHIVOLCS are working from interpreted summaries, not raw measurements.
The exact timeline of alert-level changes also has holes. Reporting confirms the initial raise from baseline to Level 1 and the current Level 3 status, but the intermediate steps and their precise dates are not fully documented in available sources. That makes it harder to judge whether the pace of escalation is accelerating, holding steady, or beginning to slow.
Bulusan’s recent track record
This is not the first time Bulusan has forced communities into an extended standoff. The volcano produced a series of phreatic eruptions between 2016 and 2017, sending ash columns over nearby towns and temporarily displacing residents. In June 2022, a more forceful phreatic eruption blanketed parts of Sorsogon in ash and prompted PHIVOLCS to raise the alert to Level 1 before the activity subsided.
That history matters because it establishes a pattern: Bulusan tends toward phreatic episodes that can persist for weeks or months, occasionally punctuated by sharper blasts, before the system depressurizes. But the pattern is not a guarantee. Each unrest episode carries the possibility, however small, of transitioning from steam-driven explosions to a magmatic eruption involving fresh lava. PHIVOLCS has not indicated that magma is currently rising toward the surface, but the agency’s conservative posture at Level 3 reflects the reality that the situation could change quickly.
The toll on Sorsogon’s farming communities
The five-kilometer exclusion zone cuts through some of the most productive agricultural land on Bulusan’s lower slopes. Coconut and abaca plantations, the economic backbone for many smallholders in the surrounding municipalities, sit inside or at the edge of the restricted area. Farmers who cannot tend or harvest their crops face losses that compound with every week the lockout continues.
No official statements from Sorsogon’s local government units quantifying economic damage have surfaced in institutional records so far. Compliance rates among residents ordered to stay out of the danger zone are also undocumented in available sources. Both gaps matter: without hard numbers, provincial and national agencies have less basis for calibrating relief programs, and journalists have less ability to hold officials accountable for the adequacy of their response.
Local governments face the difficult task of enforcing exclusion rules while providing support. Food assistance, temporary employment, and alternative planting sites outside the high-risk area are the kinds of measures that typically accompany extended volcanic lockouts in the Philippines, but none have been detailed in the current public record for Bulusan.
What comes next for Bulusan
Disaster managers are planning across a wide range of scenarios, from a gradual decline in seismic activity to a sudden, violent steam blast that could send rocks and ash cascading down the upper slopes. Because phreatic eruptions give so little warning, evacuation drills, clear communication channels, and rapid-mobilization plans remain essential even though no large ash columns have appeared during this episode.
Alert Level 3 means authorities cannot safely relax restrictions until monitoring data show a sustained, well-documented downturn in unrest. A move to Level 4 would signal that a hazardous eruption is imminent and would likely trigger wider evacuations. Level 5 means an eruption is underway.
For now, the best-supported reading of the evidence is that Bulusan is locked in a phase of elevated hydrothermal activity that justifies the current exclusion zone and the vigilance behind it. The scientific record confirms the alert level, plume behavior, and official warnings. But it leaves open critical questions about the depth and trajectory of the system driving the unrest. Until PHIVOLCS publishes more granular monitoring data or formally downgrades the alert, residents and officials must treat the volcano as capable of producing hazardous explosions with limited notice and organize daily life around that unresolved risk.
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*This article was researched with the help of AI, with human editors creating the final content.
