Bulusan volcano (File photo)
MANILA – Very weak to weak emission of white steam-laden plumes transpired at the Bulusan Volcano's active vents on the crater and summit area, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Tuesday afternoon.
It also noted that the volcanic gas activity within the edifice may potentially trigger steam-driven or phreatic eruption from any of the active vents.
At least 17 volcanic earthquakes have been recorded in Bulusan Volcano since May 7. Volcanic earthquakes are caused by movements or eruptions of magma from the volcano, compared to tectonic quakes which are caused by fault movements.
In an advisory, Phivolcs said 11 of these were volcano-tectonic earthquakes associated with rock-fracturing, while six were tornillo events associated with movement of volcanic gas. Tornillos are low-frequency earthquakes that produce a screw-like pattern on the seismograph.
These indicate volcanic gas activity is taking place beneath the edifice, Phivolcs said.
While Bulusan Volcano remains under Alert Level 0 (normal), phreatic eruptions could still occur.
The public and the local government are reminded that entry into the 4-kilometer radius permanent danger zone, particularly near the vents on the south-southeastern slopes, should be avoided due to the possibility of sudden and hazardous steam-driven or phreatic eruption, rockfall and landslide.
Those living within valleys and along river/stream channels should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall, Phivolcs warned.
Pilots are advised to avoid flying close to the volcano’s summit as ash from any phreatic eruption can be hazardous to aircraft.
Bulusan Volcano has been under the normal alert level since Jan. 18. (PNA)
