The volcano monitoring agency reported heightened unrest at Bulusan Volcano in Sorsogon after recording a total of 223 volcanic earthquakes over a 24-hour observation period on Thursday, April 23.

The data, released in its latest bulletin, indicate continued magmatic or hydrothermal activity beneath the volcano despite its current Alert Level 1 status, which signals abnormal conditions but no imminent eruption.

According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), sulfur dioxide emissions were measured at approximately 121 tonnes per day based on observations taken on Wednesday.

A weak to moderate plume reaching up to 100 meters was also observed drifting toward the western direction, while ground deformation data showed signs of ongoing volcanic stress.

PHIVOLCS noted that the recorded seismicity includes volcanic earthquakes associated with fluid movement or rock fracturing beneath the edifice, underscoring the continuing unrest within the system.

The agency reiterated that sudden steam-driven or phreatic explosions remain possible, even without clear magmatic eruption signals.

In its advisory, authorities maintained the enforcement of the four-kilometer Permanent Danger Zone (PDZ) and warned against unauthorized entry. A stricter extended danger zone of up to two kilometers on the southeastern flank remains in place due to elevated risks.

The public was also advised to avoid flying aircraft near the volcano’s summit because of potential ash or gas emissions.

Despite the elevated seismic activity, PHIVOLCS emphasized that Alert Level 1 remains unchanged, but urged residents and local government units to maintain vigilance and adhere strictly to safety protocols as volcanic conditions continue to evolve.