A week after it showed visual signs of unrest, Mount Bulusan in Sorsogon generated another steam-driven explosion yesterday afternoon.
The Philippine Institute of Volcanology and Seismology observed the steam-driven eruption at 1:03 p.m. yesterday, which lasted for approximately seven minutes and produced approximately a 300-meter high dirty white ash plume that drifted towards the northwest.
Steam-driven explosion, also called phreatic explosion, happens when groundwater is heated by magma.
Last June 10, Mount Bulusan also had a phreatic eruption that occurred at 11:35 a.m. and observed on the west-northwest vent of the volcano. A two-kilometer-high grayish ash plume, which drifted to the northwest, was visible after the explosion.
Alert Level 1, which is the lowest of a five-tier level of volcanic unrest, remains in effect over Mount Bulusan.
This indicates that hydrothermal processes are ongoing beneath the volcano that may lead to steam-driven eruptions, Phivolcs said.
It warned local government units and the public from entering the four-kilometer permanent danger zone surrounding the volcano due to possible sudden and hazardous steam-driven eruptions.
Civil aviation authorities were also advised to warn pilots to from flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft. (Ellalyn B. de Vera)