MANILA (UPDATED) — Phivolcs has recorded "short-lived lava bursts" on Mayon volcano in the past 24 hours, it said on Saturday but saw no reason to raise the alert level there from the current Alert 3.

State seismologists said the lava bursts from the Albay volcano were accompanied by seismic and infrasound signals past 6 p.m. on Friday.

Based on its 8 a.m. advisory, Phivolcs also recorded 31 volcanic earthquakes (which includes 23 tremor events), a pyroclastic density current event, and 87 rockfall events.

• Mayon shows 'no indication' for lower alert level as quiet eruption continues: Phivolcs

There were also rockfalls and pyroclastic density currents due to the collapse of the summit dome deposited debris within 4 kilometers of the crater.

Volcanic sulfur dioxide or SO2 emission, meanwhile, hit 592 tons per day, with plumes reaching 1,000 meters tall.

In a message to ABS-CBN News, Phivolcs said the lava bursts were the result of pockets of pressurized gases abruptly released instead of the continuous, active degassing.

"This is consistent with elevated sulfur dioxide gas that is being measured for Mayon. Alert Level 3 is maintained over Mayon Volcano," Phivolcs said.

In a separate advisory, Phivolcs said, "short-term observations from electronic tilt and GPS monitoring indicate inflation of the northwestern upper and middle slopes since late July 2023 and October 2023, respectively."

"Longer-term ground deformation parameters from [Exposure Database Module], precise leveling, continuous GPS, and electronic tilt monitoring indicate that Mayon is still generally inflated relative to baseline levels," it added.

Despite these activities, Phivolcs said Mayon remained on Alert Level 3, or still in a relatively high level of unrest.

"Hazardous eruption within weeks or even days could still be possible," Phivolcs said.

"Increased vigilance against pyroclastic density currents, lahars, and sediment-laden streamflows along channels draining the edifice is also advised," it said.

Phivolcs also advised the public to avoid the 6-kilometer radius permanent danger zone amid the threat of lava flows, pyroclastic density current event, rockfalls and other volcanic hazards.

Ash fall events may happen on the southern side of Mayon, based on the wind pattern, said Phivolcs.

• Residents told to prepare for possible mudflow near erupting Mayon amid rains

Pilots must also avoid flying close to Mayon's summit "as ash from any sudden eruption can be hazardous to aircraft," based on the advisory.

Some 20,00 residents inside the volcano's danger zone have fled their homes since Mayon's status was raised to Alert Level 3.

— Job Manahan, ABS-CBN News

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