MANILA – Bulusan Volcano is still under normal behavior despite volcanic activities observed in the last 24 hours, Philippine Institute of Volcanology and Seismology (Phivolcs) director Renato Solidum Jr. said Sunday.
Solidum said seismicity, ground deformation and sulfur dioxide are within background levels, and it has only been in the past two days that so-called successive “tornillos” have been recorded.
“It’s still under alert level 0 because seismicity count is within background levels, and there were no other anomalous parameters. The reason we issued an advisory is because of tornillos, a type of volcanic quake which is shaped like a screw that is associated with gas passing through cracks within the volcanic edifice,” he said in an interview.
Solidum added that ‘tornillos’ were recorded as precursors of phreatic eruptions in Bulusan before.
“The ‘tornillos’ we are recording are still very weak, compared to previous precursory ones, but we cannot discount the possibility of phreatic explosion nonetheless,” he noted.
Phivolcs recorded five volcanic earthquakes.
“We also reiterate all the time that even at quiescence, phreatic or steam-driven explosions can occur,” Solidum added.
Bulusan Volcano has been under alert level 0 since January 25. It was under alert level 1 for eight months, or from May 5, 2019 to Jan. 24, 2020.
Solidum said this was the first time Phivolcs recorded volcanic activity in Bulusan since it was placed under alert level 0.
Meanwhile, Solidum said the public should avoid entering the 4-kilometer radius Permanent Danger Zone (PDZ).
“Although there are no inhabitants within Bulusan’s PDZ, trekking to the summit is common. This activity must be avoided due to the increased possibility of phreatic eruption,” he said.