Mayon Volcano in Albay generated the largest pyroclastic density current (PDC) or “uson” on Monday morning, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).
The PDC was first recorded at 10:35 a.m., travelling down as far as a four-kilometer radial distance on the Mi-isi Gully.
“The PDC generated an extensive 1-kilometer-tall brownish ash plume that drifted to the southwest and brought ashfall over several barangays of Camalig and Guinobatan, Albay,” Phivolcs posted on social media.
Alert Level 3 (high level of volcanic unrest) is maintained over Mayon Volcano, with entry into the six-kilometer radius Permanent Danger Zone strictly prohibited.
Pyroclastics are fragmented volcanic particles. When these mix with hot gases and ash, they form what are known as PDCs.
PDCs may range from pyroclastic flows to pyroclastic surges. These are generated when an eruption column collapses under its own weight, and are more dangerous than rockfalls due to their combination of gases, ash, and rocks.
