Bulusan Nagparamdam: Alert Level 1 Up as Steam Eruption Risk Rises

Bulusan Volcano in Sorsogon has been placed under Alert Level 1 after state volcanologists said the mountain has entered a period of low-level unrest. PHIVOLCS reported that conditions beneath the volcano have changed enough to raise concern over possible phreatic or steam-driven eruptions.

According to the agency, 475 volcanic earthquakes were recorded at Bulusan from March 15 onward. Most of these were described as weak volcano-tectonic quakes linked to rock fracturing at shallow depths below the volcano, a sign that activity is building under the surface.

PHIVOLCS also said Bulusan's western and southeastern flanks have shown inflation, or pag-umbok, over the past several weeks. That pattern suggests hydrothermal processes are happening underground, which could trigger sudden steam explosions from summit vents even without a full magmatic eruption.

Because of that risk, authorities reminded the public and local officials not to enter the volcano's 4-kilometer permanent danger zone. PHIVOLCS warned that hazards from a sudden eruption could include ashfall, rockfall, ballistic projectiles, pyroclastic density currents, and avalanches.

Before Sunday, Bulusan had been under Alert Level 0 since early February. With the status now raised, residents are being urged to stay alert, monitor official bulletins, and avoid treating the volcano's quiet appearance as a sign that all is normal kasi puwedeng biglaan ang steam-driven activity.

Source: Rappler — https://www.rappler.com/philippines/luzon/phivolcs-bulusan-volcano-alert-level-march-22-2026/