LEGAZPI CITY, Albay – The Philippine Institute of Volcanology and Seismology (Phivolcs) confirmed that residents in Albay province heard rumbling sounds from Mayon Volcano before the alert level was raised from one to two on Monday, June 5.
Paul Alanis, Phivolcs resident volcanologist at the Lignon Hill Observatory here, told the Manila Bulletin in a phone interview that the rumbling sounds were caused by rockfall events in Mayon.
MAYON Volcano’s crater emits a column of cloud at past noon at Monday, June 5, in this photo taken by Claire Hariri of SM City-Legazpi. According to Paul Alanis of Phivolcs, the phreatic-like cloud at the crater was not caused by a phreatic eruption but by rockfall events.
"Ito po ay sanhi ng paggulong ng mga malalaking bato mula sa crater ng Bulkang Mayon (These rumbling sounds were caused by rocks that rolled from the crater of Mayon Volcano)," Alanis said.
Alanis said that the alert level was raised because Mayon Volcano has recorded 49 rockfall events since June 4, nine times more than the average of five rockfall events daily since April 1.
He said that Mayon has logged a total of 518 rockfall events since April 1.
"Hindi naman ibig sabihin limang rockfall events kada araw. Ito ay average lamang kung saan 518 ang total rockfall events na nai-rehistro simula April 1, 2023 (Mayon has registered a total 518 rockfall events or an average of five daily since April 1, 2023)," Alanis said.
Alanis said that the current unrest is driven by shallow magmatic processes that could eventually lead to phreatic eruptions or even precede hazardous magmatic eruption.
"Medyo mababaw na magkaroon ng big eruptions kasi wala kaming nakikitang bagong magma. ‘Yung pinaka posible ay ‘yung phreatic eruptions (The possibility of a big eruption is small because we did not see new magma. But there is a possibility of a phreatic eruption)," he added.
According to a Phivolcs advisory, based on the precise leveling, continuous GPS (Global Positioning System), and electronic tilt monitoring, Mayon is still inflated, especially in the northwest and southeast, since 2020, which means there is a current unrest that could possibly result to a dome activity.
Albay Public Safety and Emergency Management Office (APSEMO) chief Dr. Cedric Daep said that as of now, they are on monitoring status and keeping the public informed that the alert level has been raised from one to two.
"Back to Alert Level 2. No actions so far except for the public information about raising the alert status by Phivolcs," Daep said.
Philvolcs and APSEMO advised the public to be vigilant and avoid entering the six-kilometer radius Permanent Danger Zone (PDZ) to minimize risks from sudden explosions, rockfall, and landslides.