PHIVOLCS: Increased seismic activity anew at Bulusan Volcano

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Tuesday logged increased seismic activity anew at the Bulusan Volcano in Sorsogon.

In an advisory on Tuesday afternoon, state volcanologists recorded 90 weak volcano-tectonic earthquakes from 12 a.m. to 12 p.m.

Very weak to moderate degassing activities were also logged, with weak volcanic sulfur dioxide or SOz emission averaging 40 tonnes per day as of March 12.

“Nearly all of these events were weak volcano-tectonic earthquakes associated with rock fracturing within five kilometers beneath the edifice,” the advisory said.

PHIVOLCS did not observe any significant ground deformation and changes, but warned that previous phreatic eruptions of Bulusan Volcano were preceded by sporadic swarms of volcanic earthquakes.

“Given that this is the second swarm recorded this March 2026, the chances of a steam-driven or phreatic eruption occurring in the succeeding hours or days have significantly increased,” it added.

Mt. Bulusan remains at Alert Level 0 or no foreseen magmatic eruption, but PHIVOLCS said increased seismicity could trigger sudden eruptions.

State volcanologists also warned that the four-kilometer radius Permanent Danger Zone (PDZ) must be avoided due to possible eruptions.

Earlier this month, PHIVOLCS said it noted increased seismic activity such as volcanic earthquakes at Bulusan Volcano in Sorsogon but said it remains under Alert Level 0.  — JMA, GMA Integrated News