Bulusan volcano’s quakes diminishing

By Cet Dematera


After surging to over 100 seismic events last June 12, Bulusan Volcano in Sorsogon has again gradually simmered down from 27 earthquakes on Monday, June 14, 17 on June 15 and three on the day, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.


Phivolcs has been attributing these fluctuations in seismicity to “shallow hydrothermal activity following rainwater recharge into Bulusan’s hydrothermal system.”


Phivolcs resident volcanologist in Cavid-An Monitoring Station in Sorsogon City, April Dominguiano, said Bulusan’s seismic condition remains within the alert level 1 status, or abnormal.


“But we are keeping a close watch of Bulusan. Right now its activities are all still within the alert level 1 status,” Dominguiano said.


Phivolcs said that ground deformation data from continuous 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 inside the volcano’s permanent danger zone (PDZ) remains strictly banned.


Phivolcs reiterated again that “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 phreatic eruption occur.”


Southwest monsoon is now again prevailing in the Bicol region that might trigger possible flash floods or landslides due to severe thunderstorms.