A team of geologists from the central office of the Philippine Institute of Volcanology and Seismology (Phivolcs) has finished the ground deformation survey around Mayon Volcano.
In the survey at Buang Leveling line in Tabaco City, the 10 mm swelling of the volcano's edifice was maintained compared to the survey conducted last month. In the Santo Domingo leveling line in Barangay Lidong, the 4 mm inflation was also maintained.
PHIVOLCS Legazpi resident Volcanologist Ed laguerta said that the parameters indicate an active movement of magma inside the volcano which could result in a sudden minor phreatic explosion.
Aside from the swelling the crater glow was still visible.
Meanwhile Phivolcs personnel were waiting for the fly-spec (flyweight spectrometer) from their central office which they expect to arrive this week. The instrument will be used to determine the sulfur dioxide emissions from the volcano. The normal sulfur dioxide emission is reportedly 500 tons per day.
Meanwhile Phivolcs recorded eight short-duration volcanic quakes in the 24-hour period.
In its July 10 bulletin, Phivolcs said that the present seismic count is at the same level when a phreatic explosion occurred last August 2008.
Residents at the footslope of Mt. Mayon have been advised to be on alert especially those living at the southeast quadrant of the volcano. Some barangays in Legazpi City, Daraga and Santo Domingo towns in Albay provinces are located in this southeast quadrant.
Phivolcs said that the lava pile in the volcano's crater poses danger to the residents at the south east quadrant. Phivolcs explained that a continuous magma activity which could trigger small eruptions would cause the lava pile to detach. Detached lava could tehn cause pyroclastic flow which would be deadly to residents especially those farmers inside the six-kilometer permanent danger zone.
Phivolcs on Friday raised Alert Level 2 (moderate unrest) over Mayon Volcano because of an increase in the number of low-frequency volcanic earthquakes, which reportedly indicates the movement of magma beneath the volcano edifice at shallow depth. By Jose Carretero, ABS-CBN News Bicol