Mayon ashfall covers more than 8,500 hectares – PhilSA

MANILA, Philippines — The Philippine Space Agency (PhilSA) has released a map showing areas covered by ash deposits from a reported pyroclastic density current at Mayon Volcano on Saturday, May 2.

Based on its analysis, PhilSA said at least 8,544 hectares — about half the size of Quezon City — were covered by ashfall from the volcanic activity locally called “uson.”

Pyroclastic density currents are fast-moving flows of hot volcanic gas, ash, and rock fragments that descend a volcano’s slopes during eruptive activity.

The Philippine Institute of Volcanology and Seismology said ashfall — composed of fragmented volcanic particles less than 2 millimeters in diameter — “is a health hazard.”

“It is also a danger to aircraft and other industrial machinery, such as those for transportation and power generation,” it said.

The United States Geological Survey said ash fallout can significantly disrupt and damage buildings, transportation, water and wastewater systems, power supply, communications equipment, agriculture, and primary production — “even at thicknesses of only a few millimeters or inches.”

Mayon’s ashfall has so far affected 30,522 families, or 102,406 people, in 87 barangays in the Bicol region as of Monday, May 4, according to the Office of Civil Defense. /dm /atm