Phivolcs warns against lahar flow as Mayon continues to spew lava

THE Philippine Institute of Volcanology and Seismology (Phivolcs) warned residents living near river channels around Mayon Volcano to be on alert and ready to be evacuated, especially as rain is expected to continue in the coming days.

PERILOUS BEAUTY Mayon Volcano appears calm from the distance on Tuesday, July 18, 2023, but it is emitting thunder-like sounds that reverberates across the province. PHOTO BY RHAYDZ BARCIA

Dr. Teresito “Toto” Bacolcol, Phivolcs director, told the “Laging Handa” public hearing on PTV-4 that the agency has identified river channels, including in Niisi, Binaan and Anoling going to Daraga, Albay; Girangay River going to Camalig, also in Albay and Maninila River going to Guinobatan, where lahar may flow if rains caused by Typhoon “Egay” would persist in the coming days, Bacolcol said.

“That is why, we continue to remind and warn those residents living near these river channels to stay alert and be ready to be evacuated to higher grounds if torrential rains continue,” he said.

But he said that, so far, based on the inspections conducted by Phivolcs personnel in these areas, there is no indication of lahar and sediment-laden stream flows.

“But again, we must always be on alert so that we will not be caught flat-footed,” the Phivolcs official reiterated.

“Heavy rainfall could generate channel-confined lahars and sediment-laden stream flows in channels where PDC (pyroclastic density current) deposits were emplaced,” he added.

In the past 24 hours, Bacolcol said a slow effusion of lava from the volcano's summit crater continued to feed and bulk up established lava flows on the Mi-isi (south), Basud (eastern), and Bonga (southeastern) gullies.

The Mayon Volcano Network said four PDCs, 156 rock fall events and 2, 047 tons/day of sulphur dioxide (SO2) gas emission have been recorded.

While other parameters continued to slightly decrease during the last two days, the SO2 gas emission has increased as compared with the previous data, Phivolcs said.

“But this does not mean that this is already the signal for us to raise the alert status of Mayon Volcano because if we can compare it in the previous records, there were eruptions wherein gas emission would reach more than 5, 000 tons per day,” Bacolcol said.

Phivolcs said Alert Level 3 is maintained over Albay volcano, which means that it is currently in a relatively high level of unrest and hazardous eruption within weeks or even days could still be possible.

Bacolcol said the six-kilometer radius permanent danger zone around the volcano must remain free from residents evacuated due to the danger of PDCs, lava flows, rock falls, and other volcanic hazards.