LEGAZPI CITY, Albay, Philippines – Mount Bulusan in Sorsogon spewed a 150-meter high ash steam column at around 1:15 p.m. Sunday, which drifted towards four barangay (villages) in the town of Bulusan, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
Prior to the low-energy ash-and-steam ejection on Sunday afternoon, Phivolcs seismic instruments recorded three volcanic earthquakes over the last 24 hours, or until 8 a.m. of Sunday.
The Phivolcs also reported that its instruments recorded 41 quakes that were initially plotted around the northeastern side of Sorsogon province. However, these quakes were caused by movements of the local faults and “any possible relationship of these earthquakes with the current activity of Bulusan Volcano is being closely monitored and evaluated,” the Phivolcs bulletin said.
Very slight traces of ash fall were reported Sunday afternoon in the villages of San Jose, Saclan, San Rafael and Dapdap in Bulusan town, said Rachelle Miranda, spokesperson of the Office of Civil Defense in Bicol (OCD 5).
Eduardo Laguerta, Phivolcs resident volcanologist based in Legazpi City, said the 41 tremors recorded in Sorsogon, all of which had no felt intensities, would have to be closely monitored because small earthquakes faults were found in the areas surrounding Bulusan Volcano.
He said the steam pressurization underneath the volcano edifice might have triggered the movements in the local earthquakes faults. However, he stressed that this possibility would still need a thorough evaluation.
On Friday, Bulusan volcano also spewed ash, sending a 1.5-kilometer high ash plume cloud that drifted towards five villages in Juban town.
Laguerta said the eruption was a “phreatic” type similar to the four other steam-driven explosions that happened this week.
Alert Level 1 remains in effect over Bulusan Volcano, which, among others, means that the public is prohibited from entering the volcano’s 4-km Permanent Danger Zone due to sudden phreatic explosions.
Civil aviation authorities were also told to advise pilots to avoid flying close to the volcano’s summit as sudden ash eruption can be hazardous to aircraft.