LEGAZPI CITY: Mount Mayon, the country’s most active volcano, might unleash a big explosion anytime as indicated by swarming earthquakes and magma build-up, a Philippine Institute of Volcanology and Seismology (Phivolcs) official warned on Thursday.
“Phreatic explosion may happen anytime but a big explosion is expected in the coming days. The massive drying up of wells across Albay specifically in the municipalities surrounding the volcano may be attributed to the magma movement activity beneath the restive volcano,” Ed Laguerta, Phivolcs’ resident volcanologist chief in Bicol, said.
Laguerta added that the occurrence of three consecutive earthquakes in August this year that originated in Santo Domingo fault line could have affected the volcano’s sudden restive condition. The restiveness is also gauged by massive drying up of wells in several towns of Albay.
“Today, the possibility to continue for magmatic eruption is possible. We cannot discount the possibility of big
explosion. Phreatic explosions usually occur before the big explosion,” he said.
The public is prohibited within the six-kilometer danger zone from the volcano.
Mayon Volcano, with an elevation of 2,462 meters, is some 300 kilometers away from Manila noted for magmatic and explosive eruptions in the past.
Laguerta said his office requested geodetic engineers from Phivolcs central office to conduct immediate ground survey around the volcano after the three consecutive earthquakes last month.
After the survey, he told The Manila Times, they uncovered increasing amounts of sulfur dioxide, inflation of the edifice of the volcano and implication of swarm earthquakes.
“We noted after the survey that Mayon is inflated, magma beneath the volcano is building up. Deep wells are drying up surrounding the volcano and in several towns here [which is]an implication of abnormal activity,” Laguerta said.
With the findings, Phivolcs raised from zero to alert level 1 the condition of the volcano.
The Continuous Global Positioning System and tilt measurements show constant inflationary trend since July 2016 while results of precise leveling and electronic distance surveys in the last week of August 2016 indicate inflation of the edifice, possibly because of magma movement at depth.
Volcanic earthquake activity is increasing with a total of 146 earthquakes recorded by Mayon Volcano Observatory seismic network from August 3 to August 6, located on the southeast side 10 kilometers away from the volcano.
This earthquake swarm likely emanated from rock-fracturing processes that may or may not be associated with magmatic activity.
Steaming activity from the crater has ranged from weak to moderate.
Though no crater glow has been observed, Phivolcs warned of phreatic explosion anytime that could lead to a big explosive eruption.
Laguerta warned the public against entering the six-kilometer danger zone to avoid repetition of 1993 and 2014 phreatic explosions wherein 77 farmers were killed in 1993 while six foreigners, including a Filipino tourist guide, died in a sudden explosion.