PHIVOLCS lowers alert status over Bulusan, says volcano has returned to normalcy

Residents still advised to keep off 4-km permanent danger zone

Bulusan volcano when it was placed on alert level 1 after it spewed a 2-kilometer-high ash plume. (Phivolcs)

(Eagle News)–The Philippine Institute of Volcanology and Seismology has lowered the alert status of Bulusan volcano after a general decline in its activity but advised residents to still stay away from the 4-kilometer permanent danger zone.

In its bulletin on Saturday, Jan. 25, PHIVOLCS said the alert level 1 (abnormal) previously hoisted over the volcano was now an alert level 0 after a decline to baseline levels of the frequency of volcanic earthquakes since May 17, 2019, and the finding that there was no pressurization from subsurface magma.

Sulfur dioxide emission was also low, which PHIVOLCS said indicates the “depletion of volcanic gas supply from an active shallow hydrothermal or deep magmatic source.”

PHIVOLCS said “ambient carbon  dioxide(CO2) concentration is also decreasing in monitored springs around Bulusan Volcano,” which, although spewing  weakly  steam-laden plumes, was “consistent with diminished hydrothermal activity.”

PHIVOLCS said the lowering of the status means “observational parameters have returned to baseline or background levels and no magmatic eruption is foreseen in the immediate future.”

“However, in the event of a renewed increase in any one or combination of the above monitoring parameters, the alert status may step up once again to Alert Level 1,” PHIVOLCS said.

The local government units and the public, however, were still reminded that entry into the 4-kilometer radius PDZ should be avoided.

Civil aviation authorities were also told to  advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft.