Mayon still restive – Phivolcs
After more than a month of showing signs of increased activity, Mayon Volcano continues to exhibit erratic behavior manifested by lava fountains, lava flow and gas emissions.
Around 4 a.m. Tuesday, the Philippine Institute of Volcanology and Seismology (Phivolcs) recorded 56 discrete lava fountains, lasting five minutes to an hour.
A lava collapse generated white to dirty white plume at 6:16 a.m. along Basud Gully last Monday.
Phivolcs said lava flow has not advanced more than 3.3 kilometers, 4.5 kilometers and 900 meters on the Miisi, Bonga and Basud gullies, respectively.
Pyroclastic density currents or pyroclastic flows remained confined within the farthest recorded reaches of 4.6, 5.2 and 4.2 kilometers on the Miisi, Bonga and Basud gullies, respectively. Phivolcs also observed a total of 72 volcanic earthquakes, corresponding to lava fountaining and tremor events.
Sulfur dioxide emission remains high, averaging 2,148 tons per day since Monday. It tends to increase through time as magma degasses with increasing rates as it moves up from great depths beneath the volcano, Phivolcs explained.
Phivolcs pointed out that there is still a sustained swelling or inflation of the edifice since October and November 2017, consistent with pressurization by magmatic intrusion.
It continues to advise the public to be vigilant and desist from entering the eight-kilometer-radius danger zone.
It also advised civil aviation authorities to warn pilots from flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft.
Mayon Volcano remains under alert level 4 due to imminent hazardous eruption. It has been raised to level 4, the second highest alert for volcanic unrest, last Jan. 22.
Phivolcs explained that a volcano under alert level 4 means there is an “intense” unrest, manifested by persistent tremor, many low frequency earthquakes, sustained increase or abrupt decrease in sulfur dioxide emission, intense crater glow, incandescent lava dome, lava fountain, and lava flow.