Aerial Photo of Mt. Mayon taken from a PAF helicopter appears calm but report of magma buildup makes the volcano dangerous. Rhaydz B. Barcia
LEGAZPI CITY --- Mount Mayon in Albay has renewed its signs of restlessness with 16 volcanic earthquakes recorded during the past two days, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Tuesday.
The volcano’s last major eruption was recorded in January last year.
Phivolcs instruments at the Lignon Observatory recorded from Monday to Tuesday this week 16 volcanic earthquakes, six rockfall events, above normal gas emission, and bulging at the volcano’s edifice.
Eduardo Laguerta, Phivolcs resident volcanologist in an interview describes the quakes as “Low Frequency,” a movement triggered by magma build up and gas pressure.
“Low-frequency quakes are usually triggered when magma is developed and intrude inside the volcano’s vent,” he said.
Laguerta explained the quakes that occurred had two scenarios: the first had the volcano starting to “resupply” or preparing for an upcoming eruptive event. “This is a normal every time that Mayon wanted to show it restless behavior,” according to Laguerta.
The second, on the other hand, had the dome appearing at the volcano’s crater where it could be growing because of magma build up and gas.
Laguerta said these abnormalities are still being closely monitored. Presently, there is no cause for alarm that the volcano could exhibit another major eruption, he assured.
Asked if the volcano’s restlessness would be grounds for raising Mayon Volcano’s alert status to a higher level, Laguerta said this would depend on the abnormalities exhibited by the volcano in the next few days.
The parameters for raising the alert status include high and low-frequency earthquakes, gas emissions, inflation at the edifice, crater glow, and lava trickles at the volcano’s summit .
He said sulfur dioxide emission was measured at 680 tonnes a day, a bit higher than the normal level of 500 tonnes a day.
A slight bulging at the volcano’s edifice remains to be observed by Phivolcs’ Precise Leveling instrument.
Meanwhile, Alert Level 2 (moderate level of unrest) remains hoisted over Mayon.
Phivolcs warned the public to keep out of the 6-kilometer permanent danger zone (PDZ) around the volcano, as well as the precautionary 7-km Extended Danger Zone as sudden explosions, lava collapses, pyroclastic density (PDCs) and ashfall could still occur and threaten areas in the middle and upper slopes.
Active stream/river channels and those identified as perennially lahar-prone areas on all sectors of the volcano should also be avoided especially during extreme weather conditions when there is heavy and prolonged rainfall.
Civil aviation authorities must advise pilots to avoid flying close to the volcano’s summit as airborne ash and ballistic fragments from sudden explosions and PDCs may pose hazards to aircraft.
“For the past several months the volcano has been showing different behaviour compared to last year after the eruption that’s why we’re closely watching the volcano because of magma build up,” Solidum said.
A slight bulging at the volcano’s edifice is being observed by Phivolcs’ precise leveling instrument while sulfur dioxide emission was measured at 680 tonnes a day, a bit higher than the normal level of 500 tonnes a day.
Phivolcs reminded the public to keep out of the six-kilometer permanent danger zone around the volcano and the seven-kilometer extended danger zone in the south-southwest to east-northeast sector, as sudden explosions, lava collapses, pyroclastic density and ashfall could still occur and threaten areas in the upper to middle slopes.