Mt. Bulusan continues to show uptick of volcanic quakes — Phivolcs

MANILA, Philippines — Mount Bulusan in Sorsogon province has continued to show an increase in volcanic earthquakes, state seismologists said on Tuesday.

A total of 91 volcano-tectonic earthquakes “associated with rock fracturing” with a depth of two to four kilometers have been recorded since 1:38 a.m. on Monday, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

“Increased seismic activity and pressurization of the volcano edifice may indicate that hydrothermal processes may be occurring beneath the volcano and may lead to steam-driven eruptions at any of the summit vents,” Phivolcs said in a statement.

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Also, the volcano’s southwestern and southeastern flanks have been inflated since Feb. 2023 based on Phivolcs’ ground deformation data from continuous GPS and electronic tilt monitoring.

On the other hand, Phivolcs said degassing activity from the summit crater and active vents has been very weak to moderate when the volcano summit has been visible.

Considering these factors, the state volcanologist said Bulusan volcano remains under alert level 1, meaning it is still at a low level of unrest.

READ: Mount Bulusan: Phivolcs detects 71 ‘rock fracture-linked’ quakes