(UPDATE) LEGAZPI CITY, Philippines—Mt. Bulusan in Sorsogon continued to show indications of “restiveness” as five volcanic earthquakes, including an explosion-type tremor, were noted by the Philippine Institute of Volcanology and Seismology (Phivolcs) for the past 24-hour period.
The volcano also exhibited a slight inflation at its edifice since May this year, indicating that steam-driven pressure could be building up beneath the volcano’s vent, Ed Laguerta Phivolcs, resident volcanologist, said Saturday.
Laguerta explained that steam-driven or “phreatic” eruptions may happen when hydrothermal processes continue to develop beneath the volcano.
Aside from volcanic quakes and bulging at the edifice, Phivolcs’ instruments recorded the volcano expelled weak to moderate white steam plumes that rose up to 150 meters and drifted towards north-northwest portion of the volcano during the past 24-hour monitoring period.
Mt. Bulusan on Friday belched a 2-km high grayish ash plum that drifted and fell over villages of Anog in Juban town and Mabini in Casiguran town.
READ: Mt. Bulusan belches ash over 19 villages
Municipal disaster risk reduction and management offices in Casiguran and Juban reported that around 18,575 residents in 19 villages there were affected by ashfall.
READ: More than 18,000 affected by Bulusan’s ashfall in Sorsogon
Alert Level 1 raised by Phivolcs remains in effect over Mt. Bulusan as Sorsogon Provincial Disaster Risk Reduction and Management Office (PDRRMO) is still on “blue” alert. RAM