PHIVOLCS: Mayon had zero earthquake but 299 rockfall events in past 24 hrs

Mayon Volcano remained restive over the past 24 hours, producing 299 rockfalls and eight dome-collapse pyroclastic density current (PDC) events amid "very slow" lava effusion, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said Thursday.

There was zero volcanic earthquake recorded during the same period, but the latest number of PDC events was higher compared to the seven PDC events reported on Wednesday.

“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,” PHIVOLCS said in its 8 a.m. bulletin on Thursday.

PHIVOLCS said two very slow effusions of lava flow from the crater were observed along Mi-isi gully extending 2.5 kilometers and along Bonga gully extending 1.8 kilometers.

Lava collapse on both gullies, it added, was also seen within 3.3 kilometers from the crater.

A moderate emission of plumes reaching up to 750 meters was observed over the volcano drifting to the southwest direction, PHIVOLCS said.

The sulfur dioxide (SO2) emission from the volcano increased to 574 tons on Wednesday from 507 tons on Tuesday.

PHIVOLCS 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 also warned of possible pyroclastic density currents, lahars, and sediment-laden streamflows along channels draining the edifice.

Heavy rainfall could generate channel-confined lahars and sediment-laden streamflows in channels where PDC deposits were emplaced.

Pilots should be prohibited from flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft, according to PHIVOLCS.

Ash fall events may most likely occur on the south side of the volcano considering the current prevailing wind pattern, it added.

Alert Level 3 in Mayon Volcano was raised on June 8 after three PDC events on the Bonga (southeast) and Basud (east) Gullies of Mayon Volcano.

A total of 38,989 people or 10,112 families in 26 barangays in Bicol were affected by the activity of Mayon Volcano, the National Disaster Risk Reduction and Management Council (NDRRMC) reported on Thursday.

NDRRMC report

The NDRRMC said 18,736 persons or 5,337 families were staying in 28 evacuation centers, while 1,413 individuals or 403 families were taking shelter in other places.

A total of 1,022 livestock animals were also preemptively evacuated.

A state of calamity was declared in 18 cities and municipalities due to the threat of Mayon.

Assistance worth P77,462,360 has been provided to the victims, according to the NDRRMC. —Joviland Rita/KBK, GMA Integrated News