By AARON B. RECUENCO
STO. DOMINGO, Albay – Mayon Volcano has been showing signs of slowing down, but volcanologists are not ready to conclude that the situation is normalizing.
The Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday said it wants to make sure the consistency of the data feed from their instruments by sending field scientists to conduct confirmatory tests and collect new data from instruments installed near Mayon.
Ed Laguerta, Phivolcs resident volcanologist, said among the data they observed is the decrease in the emission of sulfur dioxide from the volcano crater – from 3,066 tons a day on Feb. 1 to an average of 1,500 tons a day in the past two days.
But the most significant data collected was from geologists who reported a one millimeter deflation on the edifice of
Mayon on its northern side.
This means a decrease in the pressure inside the volcano as there may not be much resupply of magma to the Mayon’s chamber.
“If this trend will continue, then it would be better because this means a gradual slowing down of the volcanic activities,” said Laguerta.
“But again, this could just be a pause so to make sure, we will reconfirm our data,” he added.
Prior to the Jan. 22 hazardous eruption that prompted volcanologists here to hoist Alert Level 4 over Mayon, a decrease in Mayon activities was also monitored.
Among data that Phivolcs wanted to confirm is the consistency of the downtrend in the deflation of Mayon edifice.
The deflation should also be supported by a decrease in emission of sulfur dioxide and other pyroclastic materials.
The continuous deflation and decrease in the materials being spewed by Mayon would mean there is not much magma supply.
What could be left is the old supply that remains in the two-kilometer passage heading towards the crater. Mayon is some 2.4 kilometer high.
This is the reason why there is a continuous lava flow despite a possible decrease in the supply of magma.
“If there will be no additional intrusion, the lava flow will eventually stop,” said Laguerta.
The crater of the volcano, however, is not visible yesterday due to thick cloud that covered Mayon the whole day.
But near the Phivolcs station in Sto. Domingo town, which is within a five-kilometer distance from the crater, burning vegetation as a result of lava flow is noticeable.