LEGAZPI CITY — The Philippine Institute of Volcanology and Seismology (Phivolcs) raised Mayon Volcano’s alert level status from 0 to level 1 Thursday morning after noting abnormalities in its behavior but allayed fears of an imminent eruption.
Monitoring by Phivolcs’ instruments showed an increase in steam emissions at the crater, slight swelling at the base or slopes and drying up of water wells at the southeastern section of the volcano, according to Eduardo Laguerta, Phivolcs resident volcanologist at the Lignon Hill Observatory here.
He said these parameters prompted the raising of the alert level from 0, which means normal, to level 1, which in Phivolcs’ terms means “abnormal”.
Laguerta, however, said the abnormalities detected by the agency’s instruments were no indication of an imminent eruption as the other “parameters being reviewed by Phivolcs are not yet present.”
No crater glow, locally referred to as “banaag”, has been observed so far, he said.
Phivolcs, in its advisory, reiterated that the six-kilometer Permanent Danger Zone (PDZ) is a no-entry zone to the public because of the perennial danger of life-threatening rockfalls, avalanches, ash puffs and sudden phreatic or steam-driven eruptions.
The raising of the volcano’s alert level prompted the Provincial Disaster Risk Reduction and Management Council (PDRRMC) to issue an advisory today that strictly prohibits “any human activity” inside the six-km PDZ at the slopes of the volcano.
Albay Governor and PDRRMC head Al Frances Bichara directed local disaster councils, various village chiefs and police and military authorities to enforce the “no human activity” inside the designated PDZ, which include mountain climbing, farming, orchids gathering and ATV (all-terrain-vehicle) tour activities.
He also directed the disaster councils of the cities of Legazpi, Ligao and Tabaco and the towns of Daraga, Camalig, Sto. Domingo, Malilipot and Guinobatan to be on alert and to closely monitor advisories released by Phivolcs and PDRRMC.
“The agency’s instruments have been noting ‘slight ground inflation’ or swelling at the base or slopes of the volcano since July, said Phivolcs in its bulletin.
Laguerta said steaming activity from the crater has ranged from weak to moderate.
“Sulphur dioxide (SO2) emission has consistently increased beyond the baseline level of 500 tonnes per day, exceeding 1,000 tonnes per day,” Phivolcs noted in its bulletin.
Laguerta explained that SO2 emission increases through time as magma degasses with increasing rates as it moves up from great depths beneath the volcano.
Phivolcs said the seismic network recorded from August 3 to 6 a total of 146 earthquakes, that were located some 10 kms away at the southeastern section of Mayon Volcano.
“Earthquake swarm likely emanated from rock-fracturing processes that may or may not be associated with magmatic activity,” said Laguerta.
He said four of the 14 monitored water wells located on the southeastern side of Mayon are experiencing “a decrease in water discharge” while one well has dried-up. Connie Destura/PNA/northboundasia.com