PHIVOLCS: Uson, rockfall observed on Mayon Volcano

Several incandescent lava collapse-fed pyroclastic density currents (PDC) or “uson” and rockfall were observed on Mayon Volcano Thursday evening, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported.

The “uson” and rockfall, the agency said occurred on the Mi-isi (south), Bonga (southeast) and Basud (east) Gullies on Mayon Volcano between 06:45 PM to 07:45 p.m.

"A total of 60 PDCs and 229 rockfall events have been recorded by the Mayon Volcano Network as of 8:00 pm.," PHIVOLCS said.

"Alert Level 3 prevails over Mayon and entry into the 6-km Permanent Danger Zone must be prohibited," the agency added.

On Thursday morning, the agency reported a total of 207 rockfall events have been recorded, which is lower compared to the 209 from Wednesday’s report.

A total of 27 PDCs were also recorded, which is also lower than the 46 reported on Wednesday.

PDCs are mixtures of fragmented volcanic particles (pyroclastics), hot gases, and ashes that rush down the volcanic slopes or rapidly outward from a source vent at high speeds. — BAP, GMA Integrated News