April 7, 2016
MANILA, Philippines – The Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday said Bulusan Volcano in Sorsogon province continued to show signs of restiveness as more volcanic earthquakes were recorded in the past 24 hours.
Mariton Bornas, chief of the Phivolcs’ Volcano Monitoring Division, said at least 74 volcanic tremors were recorded around Bulusan from 7 a.m. Tuesday to 7 a.m. Wednesday.
Bornas said this number was significantly higher compared to the 20 quakes that were monitored from Monday morning to Tuesday morning.
She noted that the increased seismic activity in Bulusan could be a precursor to another steam-driven or phreatic eruption.
With alert level 1 still in effect in Bulusan, she said minor steam and ash explosions could happen anytime.
In its bulletin, Phivolcs said weak emission of white steam plumes that drifted southwest was observed in Bulusan since Tuesday morning.
The agency further noted that latest ground deformation survey also indicated a slight deflation of the volcano’s edifice.
Phivolcs reminded the public not to enter the volcano’s four-kilometer permanent danger zone.
The agency also advised people residing near valleys and river channels, especially on the southwest and northwest sectors of the edifice, to be vigilant against sediment-laden stream flows and lahars in the event of heavy and continuous rainfall.
Civil aviation authorities have been told to warn pilots against flying close to the volcano’s summit as ejected ash and volcanic fragments from sudden explosions may pose hazards to aircraft.
Two successive minor eruptions occurred at Bulusan last February 22, but only one of the events produced ash-laden steam clouds that rose up to 500 meters above the crater.
The said volcano is generally known for its sudden steam-driven or phreatic explosions.
Except in 1918, when a major magmatic eruption occurred and lava flow was reported in Bulusan, Bornas said.