Glowing lava flow, ‘uson,’ rockfall seen on Mayon Volcano on Day 21 of effusive eruption

The Mayon Volcano in Albay on Tuesday continued its effusive eruption for the 21st consecutive day, generating incandescent lava flows, rockfall, and pyroclastic density currents (PDCs) or “uson,” the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said.

In social media posts, PHIVOLCS shared photos of the volcano taken between 8:15 p.m. to 8:17 p.m. Tuesday which showed the incandescent lava flow and “uson” descending its slopes.

In particular, the lava flows, PDCs, and rockfalls were observed in the Mi-isi (south), Bonga (southeast) and Basud (east) Gullies.

PHIVOLCS also shared a time-lapse video of the effusive eruption from 8:01 p.m. to 8:08 p.m.

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

PHIVOLCS also logged 272 volcanic earthquakes, 155 rockfall events, and PDCs as of Tuesday morning. It also observed a crater glow, plumes, and ground deformation of the volcano.

In separate social media posts, PHIVOLCS said it regularly measures baselines using electronic distance meters (EDM) along the slopes of Mayon Volcano to gain insight into its ground deformation.

“Changes in these baselines may signify inflation which can be related to the subsurface processes beneath the volcano, such as magmatic intrusions,” it explained.

The agency also regularly monitors the volcano’s sulfur dioxide emissions. Sulfur dioxide is a primary gas component of magma and is mostly released as the magma approaches the surface. — JMA, GMA Integrated News