Bulusan abnormal signs continue
By Cet Dematera
Bulusan Volcano in Sorsogon continues to display fluctuating abnormal signs as it recorded at least 103 volcanic earthquakes in the past five days, bulletins released until June 28 by the Philippine Institute of Volcanology and Seismology (Phivolcs) showed.
The Bulusan Volcano Network (BVN) detected 22 volcanic earthquakes on June 24, surged to 47 on June 25, then dropped to 20 on June 26, dropped further to seven on June 27, then seven again on Tuesday, June 28.
Emissions of sulfur dioxide (SO2) and plume were also sustained in high levels with an accumulated volume of 2,920 tons and 1,200 meters, respectively, in five succeeding monitoring days, Phivolcs reported.
Phivolcs said that this sustained abnormal behavior could lead to a sudden and hazardous phreatic eruption at any time.
The increased number of volcanic quakes and plume emissions means degassing and hydrothermal activities are ongoing inside the volcano, Phivolcs said, adding that Bulusan’s surface remains inflated.
Renato Solidum, Phivolcs officer-in-charge, said though that as long as SO2 emissions were not yet very high, then there is no magma ascending to the surface.
“We are closely watching the SO2 emissions to determine whether magma is already ascending to the surface. So far, we don’t see that indication yet,” Solidum told Bicol Mail.
He said that the types of earthquakes and tremors that are detected are also being closely analyzed.
If these tremors are detected in the lower and upper elevations of Bulusan, then there is magmatic ascent to the surface, he added.
“But these tremors must be detected in all the monitoring instruments in the lower and upper elevations to say that there is active movement inside the volcano. Right now, we don’t see yet these activities,” Solidum explained.
But he was quick to warn that phreatic eruptions are possible any time due to the high values of Bulusan abnormal parameters.
“The volcanic earthquakes, and the volumes of SO2 and plume emissions are already considered high to trigger phreatic eruptions. That’s why we are emphasizing in our advisories not to enter inside the four-kilometer radius Permanent Danger Zone (PDZ) and the two-kilometer Extended Danger Zone (EDZ),” the Phivolcs chief added.
Reminded the public that phreatic eruptions could take place on Bulusan under alert level one.