Mayon Remains A Threat — Phivolcs

By Ed De Leon, Jen Jorvina, and Madel Sabater

The Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday warned the public that volcanic explosions and life-threatening pyroclastic flows still remain a possibility as rockfalls and lava flow continue in the vicinity of the restive Mayon volcano.


"Explosions are still very possible and the probability of life-threatening pyroclastic flows resulting from an explosive eruption remain high," Phivolcs said.

A pyroclastic flow is a volcanic hazard described as a trigger-directed blast forming hot rocks and gases down the volcano’s slopes.

According to Phivolcs, 250 tremor events had been recorded in Mayon during its 24-hour observation period, higher than the other day’s 100 short duration harmonic tremors.

The volcano’s sulfur oxide emission also escalated to 2,157 tonnes per day (t/d), which is "to be expected from an ongoing eruptive activity," Phivolcs said.

The institute also disclosed that lava flow in Bonga Gulley, the southeastern sector of the volcano, had been at 1,200 meters elevation or a little less than three kilometers (kms) from the crater as of press time.

"Lava fragments detaching from the flowing lava have reached farther downslope about four kms or more from the crater," the institute said.

Phivolcs, however, assured that all flows and rockfall activity are "occurring well within the six-km Permanent Danger Zone (PDZ)."

Phivolcs said Alert Level 3 is still hoisted over Mayon volcano, adding that the public is still barred from the six-km PDZ, except for the volcano’s southeast sector or the Bonga Gulley, where a seven-km PDZ had been imposed.

"The crater is lowest at the southeast stream," Solidum said.

Meanwhile, in Legazpi City, Albay, boulders of Mayon volcano as big as houses are seen trapped at its mid-section, some four kilometers from the crater or approximately estimated 3,000 meters at elevation 700 meters above sea level in Bonga Gulley.

"It is very dangerous for these boulders to stay at the mid-section of the volcano because the lava continues to push down the boulders towards Bonga Gulley," an official of the Phivolcs said yesterday during an inspection at the Bonga Gulley.

At the inspection with media, Phivolcs said that boulders as big as houses and lava fragments have reached further down the slope of Mayon volcano, about four kilometers below the crater. These boulders will go down to the Bonga Gulley when it rains hard.

The Phivolcs said that all flows and rockfall activities are occurring well within the six-kilometer radius PDZ, adding that light ash falls derived mainly from the lava fragments may be experienced over areas beyond the PDZ due to prevailing winds.

The Phivolcs said that there are some 13.9 million cubic meters of volcanic debris around the slopes of Mayon.

Alert Level 3 remains hoisted over Mayon. Residents were advised to be vigilant against explosive eruptions and to be prepared for evacuation any time.

[Source]