48 rockfall events recorded at Mayon due to collapsing lava front, shedding from lava dome

The Mayon Volcano's lava front and margins continued to collapse over the past 24 hours, generating 48 rockfall events and two pyroclastic flows within the same period, said the Philippine Institute for Volcanology and Seismology (PHIVOLCS) Thursday.

Mayon's seismic monitoring network also recorded one volcanic earthquake in the past days, PHIVOLCS said in its 8 a.m. bulletin.

The rockfall, pyroclastic flow events and the "persistent" lava disintegration on the Miisi lava flow generated ash clouds that drifted southwest of the volcano.

"Rockfall events were generated by the collapsing lava front and margins of the advancing lava flow on the Miisi Gully and by shedding from the summit dome onto the Matanag and Buyuan Gullies," the bulletin said. 

Alert Level 3 is still hoisted over the Mayon, and state volcanologists continue to warn of a high level of unrest as magma is at the volcano's crater. A hazardous eruption within weeks or days remains possible.

Both the Miisi lava flow and pyroclastic flows, or pyroclastic density currents, have reached approximately three kilometers from the summit crater, still well within the six-kilometer Permanent Danger Zone (PDZ).

As of Wednesday, scientists measured sulfur dioxide gas emission to be at an average of 1159 tonnes per day.

The public is reminded anew not to enter the PDZ, as well as the seven-kilometer Extended Danger Zone on the southern side of the volcano "due to the danger of rockfalls, landslides and sudden explosions or dome collapse that may generate hazardous volcanic flows."

The PHIVOLCS also urged vigilance against pyroclastic density currents, lahar, and streamflows filled with sediments along the volcano's channels.

Pilots are again advised to avoid flying close to the volcano's summit on account of dangerous ash generated by possible sudden eruptions.

Nearly 40,000 people have been displaced, the National Disaster Risk Reduction and Management Council said Wednesday. —Nicole-Anne C. Lagrimas/KG, GMA News