MANILA - Alert level 1 has been lifted off Mt. Bulusan in Sorsogon, indicating that an eruption seems unlikely in the future, state seismology bureau Phivolcs said Saturday.
In a volcano bulletin, Phivolcs explained that magmatic eruptions are unlikely in the immediate future at the volcano, which had shown activity in recent years, including an ash explosion in 2016.
The downgrade in the Sorsogon volcano came as Phivolcs continued to closely monitor activity at the Taal Volcano in Batangas, which remains under alert level 4, warning of a possible hazardous explosion in hours or days. It spewed ash in a Jan. 12 steam-driven eruption, prompting mass evacuations.
"Observational parameters have returned to baseline or background levels and no magmatic eruption is foreseen in the immediate future," Phivolcs said.
Phivolcs said volcanic earthquakes around the area "has declined to baseline levels" since May 2019. This, according to Phivolcs, indicates that rock fracturing has "diminished."
Hydrothermal activity has also "diminished" around the volcano area, Phivolcs added.
Ground deformation around the volcano also indicates "that there is no pressurization from subsurface magma, with the deformation observed in the mid-slopes most likely due to seasonal changes within the shallow hydrothermal system," according to the bulletin.
Gas emissions around the volcano has also decreased, according to Phivolcs, characterized by "weak emission of steam-laden plumes consistent with diminished hydrothermal activity."
Sulfur dioxide emission "has also remained below detection levels since 2018."
Phivolcs, however reminded the public to keep off the 4-kilometer radius Permanent Danger Zone in case another eruption becomes imminent, and for pilots to avoid flying over the volcano's summit.
Phivolcs last May raised alert levels around the volcano because of changes in Mt. Bulusan's condition.