MANILA, Philippines — Increased seismic activity has been observed anew in Bulusan Volcano in Sorsogon.
“The seismic parameters indicate that shallow hydrothermal activity is underway and may lead to steam-driven or phreatic eruption,” the Philippine Institute of Volcanology and Seismology (Phivolcs) said in an advisory.
State volcanologists said 71 volcanic-tectonic earthquakes associated with rock fracturing have been recorded since 5 a.m. yesterday.
The quakes had magnitudes ranging from 0.3 to 2.2, which occurred between one to six kilometers beneath the southern flank of the edifice of the volcano.
Phivolcs said continuous degassing activity from the summit crater generated weak to moderate plumes in the active vents.
Bulusan remains under Alert Level 1 or low-level of unrest.
Phivolcs said entry into the four-kilometer-radius permanent danger zone should be prohibited.
It warned the public against sediment-laden stream flows and lahar during heavy rainfall.