UNREST. Bulusan Volcano in Sorsogon province in this undated photo. Bulusan Volcano is showing an increase in seismic activity anew, the Philippine Institute of Volcanology and Seismology said Tuesday (Jan. 23, 2024). (File photo courtesy of Atty. Annalyn Sherry Hibo Gamboa)
MANILA – Bulusan Volcano is showing an increase in seismic activity anew, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Tuesday.
In an advisory issued at 1:30 a.m. Phivolcs said 91 volcano-tectonic earthquakes, associated with rock fracturing at 2 to 4 kilometers (kms) depth beneath the southwestern flanks, were recorded since 1:38 a.m. on Jan. 22.
The 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.
This is the second time this month that Phivolcs has observed increased seismicity in Bulusan. The first was on Jan. 11.
Bulusan had an average of 0 to 5 earthquakes a day before Jan. 11.
Meanwhile, degassing activity from the summit crater and active vents has been very weak to moderate when the volcano summit has been visible.
Alert Level 1 is maintained, which means the volcano is at low-level unrest with increased chances of steam-driven or phreatic eruptions.
Entry into the 4-km danger zone should be prohibited while vigilance must be exercised in the 2-km. extended danger zone on the southeast sector.
Aviation authorities are urged to advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft. (PNA)
