MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) said Thursday it is closely monitoring Bulusan Volcano in Sorsogon following an increase in seismic activities.
Seventy-one volcanic earthquakes associated with rock fracturing, ranging from magnitude 0.3 to 2.2 have been recorded since 5 a.m. Thursday, Phivolcs said.
It added that degassing activity from the summit crater and active vents generated weak to moderate volume plumes.
“The seismic parameters indicate shallow hydrothermal activity is underway and may lead to steam-driven or phreatic eruption,” the institute said.
Last week, the Phivolcs also reported increased activities at Bulusan.
Bulusan is under Alert Level 1, which means it is in a state of low-level unrest, with an increased likelihood of stream-driven or phreatic eruptions.
Phivolcs reminded local government units and the public that entry into the four-kilometer radius Permanent Danger Zone should be prohibited, and that vigilance in the two-kilometer Extended Danger Zone on the volcano’s southeast sector must be exercised “due to the possibilities of sudden and hazardous phreatic eruptions.”
It added that civil aviation authorities must also advise pilots to avoid flying close to Bulusan’s summit as ash from any sudden steam-driven eruption can be hazardous to aircraft.
“Furthermore, people living within valleys and along river/stream channels should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur,” the agency said.