The Philippine Institute of Volcanology and Seismology (Phivolcs) has detected six volcanic earthquakes in the vicinity of Bulusan Volcano in the past 24-hour observation period.

Phivolcs said that ground deformation data recorded sustained inflation of the volcano’s upper slopes that began on March 6, which is consistent with short-term inflation of the edifice since February.

“These parameters generally indicate that shallow hydrothermal processes are occurring beneath the edifice,” the agency said in its volcano bulletin on May 13.

Phivolcs said Alert Level 1 status remains over Bulusan Volcano, “which means that it is currently in an abnormal condition.”

The agency advised local government units and the public not to enter into the 4-kilometer radius Permanent Danger Zone of the volcano.

Likewise, Phivolcs said the public should remain vigilant when entering the two-kilometer extended danger zone on the southeast sector due to increased possibilities of sudden and hazardous phreatic eruptions.

Civil aviation authorities were also asked to advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft.

Furthermore, people living within valleys and along river/stream channels especially on the southeast, southwest, and northwest sector of the edifice should vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur.