(Eagle News) — The Philippine Institute of Volcanology and Seismology has lowered the alert level of Bulusan to “normal” following a “general decline in monitoring parameters.”
According to PHIVOLCS, in particular, volcanic earthquake activity declined to the baseline level of two to three earthquakes per day between July 1 and Aug. 17, during which a total of only 109 weak events were recorded.
PHIVOLCS said this indicates that “rock fracturing within the volcanic system associated with shallow hydrothermal activity has diminished.”
Continuous GPS measurements also showed a short-term inflation of the Bulusan edifice since July 2020, with horizontal changes indicating that ground deformation has been driven by tectonic processes.
Sulfur dioxide emission or SO2 flux from active vents on Bulusan was also below detection levels since May 6, with steam plume emissions “very weak to weak.”
“In view of the above, PHIVOLCS-DOST is now lowering the alert status of Bulusan Volcano from Alert Level 1 to Alert Level 0. This means that observational parameters have returned to baseline levels and no magmatic eruption is foreseen in the immediate future,” PHIVOLCS said.
The public was, however, still reminded to avoid entry into the 4-kilometer Permanent Danger Zone or PDZ “due to perennial hazards of rockfalls, avalanches and sudden steam-driven or phreatic eruption from any of the active vents which may occur without warning.”