Bulusan Volcano in Sorsogon (Photo courtesy of Noni Enolva)
LEGAZPI CITY – After logging over 100 seismic events last June 12, Bulusan Volcano in Sorsogon has gradually simmered down, with 27 earthquakes recorded on June 14, and only four in the past 24-hour monitoring period, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported on Monday.
Phivolcs attributed these fluctuations in seismicity to “shallow hydrothermal activity following rainwater recharge into Bulusan’s hydrothermal system.”
In an interview on Monday, April Dominguiano, resident volcanologist at the Cavid-an monitoring station in Sorsogon City said: “But we are keeping a close watch of Bulusan. Right now its activities are all still within the alert level 1 status".
Phivolcs said ground deformation data from continuous Global Positioning System (GPS) measurements indicate short-term inflation or bulging of the surface of Bulusan since May 2021.
“Tilt data from the upper slope show sustained inflation since 6 March 2021,” Phivolcs added.
Entry into the volcano’s four-kilometer permanent danger zone (PDZ) remains strictly banned.
Dominguiano said “people living within valleys and along river or stream channels, especially on the southeast, southwest and northwest sectors of the edifice should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should a phreatic eruption occur.” (PNA)
