MANILA, Oct 25 — The Philippine Institute of Volcanology and Seismology raised the alert level today over Bulusan volcano in Sorsogon province, southeast of Manila, from zero to one after it recorded 121 volcanic earthquakes since October 14.
“It means that the volcano is currently in a state of low-level unrest,” it said in an advisory, according to Xinhua.
Of the 121 volcanic earthquakes, 37 were volcano-tectonic earthquakes associated with rock fracturing processes at depths of one to nine km beneath the northwestern and southeastern slopes of the volcano edifice.
The institute also observed inflation of swelling of the volcano’s southern flank since February and of the northeastern flank since September.
A notable increase in volcanic carbon dioxide concentrations from June to August was also observed. It detected spring temperature on the southwestern slopes in February.
“These parameters indicate that hydrothermal activity driven by deep-seated magma degassing may be occurring beneath the volcano and may lead to steam-driven eruptions at any of its summit vents,” it said.
The institute warned people to stay away from a four-km radius danger zone of the volcano. It also urged vigilance in the two-km extended danger zone on the southeast sector due to the increased possibilities of sudden and hazardous phreatic eruptions.
Bulusan volcano is 70 km southeast of the Mayon volcano, the most active Philippine volcano in Albay province. Mt. Mayon has been quietly erupting since June this year and continues to be on alert three on a scale of five, with a “potential explosive activity”.
— Bernama
