LEGAZPI CITY -- The Philippine Institute of Volcanology and Seismology (Phivolcs) has lowered its alert status for Mayon volcano to Level 2.
A Phivolcs advisory issued on Thursday said the lowering of Mayon Volcano’s status from Alert Level 3 (decreased tendency towards hazardous eruption) to Alert Level 2 (moderate level of unrest) was due to the continued decline in the volcano’s activities "based on the monitored parameters, such as volcanic quakes, magma build-up, gas emission, crater glows, lava flows, and ground deformation”.
In view of the lowering of Mayon Volcano’s alert status, Albay Governor Al Francis Bichara also issued an advisory that “the Provincial Disaster Risk Reduction Management Council of Albay therefore orders thru their mayors: Tabaco City, Camfalig, Malilipot, and Guinobatan the full decampment of evacuees from 6-km radius permanent danger zone”.
Mayon's volcanic earthquake activity has waned from a peak of 82 to less than 10 rockfall events attributed to the collapse of unstable lava flow deposits on the Miisi, Bonga and Basud drainage systems, added the Phivolcs advisory.
Low frequency earthquakes associated with magma degassing and short ash plumes were last recorded last March 15, although lava flow from the crater could be detected until last March18, said the same advisory.
The overall decline in seismicity indicated that “there is currently no active transport of eruptible magma” to the mouth of the volcano.
Since the last observation of lava effusion on March 18, there was no new lava detected on Mayon’s summit crater, the advisory added.
Crater glow has likewise diminished from intense to faint.
“Gravity-driven lava flow has begun to stabilize, producing less rockfall and infrequent pyroclastic density currents, the last of which occurred on 27 March 2018,” the advisory said.
The Phivolcs, however, said the lowering of the alert status should not be interpreted to mean that the volcano’s unrest has ceased.
Alert status may be stepped up to Level 3 again if there is a resurgence of volcanic unrest or could be lowered further if the volcano’s activity would continue to decrease. (PNA)
