Mayon Volcano logs 254 rockfall events in past 24 hours —PHIVOLCS

A total of 254 rockfall events were recorded in Mayon Volcano in Albay in the past 24 hours, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said Saturday.

In its 8 a.m. bulletin, PHIVOLCS said that in the past 24-hour observation period, very slow effusion of lava from the summit crater of the volcano continued to feed lava flows on the Mi-isi (south) and Bonga (southeastern) gullies as well as rockfall and pyroclastic density currents or PDCs on these and the Basud (eastern) gully.

The number of rockfall events was lower than the 284 recorded as of Friday morning.

The PHIVOLCS also recorded 17 dome-collapse pyroclastic density currents (PDCs) and 65 weak volcanic earthquakes.

On Friday early evening alone, four dome-collapse PDCs from Mayon Volcano's summit lava dome have been recorded.

In a volcano advisory at 8 p.m., PHIVOLCS said the four PDCs were observed since 6:09 p.m. and flowed for four minutes down the Basud Gully over a distance of three to four kilometers.

“Sulfur dioxide (SO2) emission averaged 1,002 tonnes per day yesterday and was first detected in significant concentrations by satellite monitors on 29 June 2023,” it said.

“Lava flows advanced to approximate lengths of 2,230 meters and 1,300 meters along Mi-isi and Bonga gullies, respectively, from the summit crater while collapse debris deposited to 3,300 meters from the crater,” it added.

The PHIVOLCS said Alert Level 3 is maintained over Mayon Volcano, which means that it is currently in a relatively high level of unrest as magma is at the crater and hazardous eruption within weeks or even days is possible.

“It is therefore recommended that the six-kilometer radius Permanent Danger Zone (PDZ) be evacuated due to the danger of PDCs, lava flows, rockfalls and other volcanic hazards,” it said.

“Increased vigilance against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice is also advised. Heavy rainfall could generate channel-confined lahars and sediment-laden streamflows in channels where PDC deposits were emplaced,” the agency said.

The PHIVOLCS added that civil aviation authorities must advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft.

“Based on the current prevailing wind pattern, ash fall events may most likely occur on the south side of the volcano. DOST-PHIVOLCS maintains close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders,” it said. —Ted Cordero/KG, GMA Integrated News