Mayon Volcano's alert status down to Level 2

MANILA, Philippines: Following weeks of «general decline» in unrest, the Philippine Institute of Volcanology and Seismology (Phivolcs) on Friday downgraded the alert status of Mayon Volcano in Albay province to Level 2.

Phivolcs Director Teresito Bacolcol told The Manila Times that the volcano's monitoring network and observation of its day-to-day conditions have recorded a general decline in unrest since last month.

As a result, he said, Phivolcs has lowered its status from Alert Level 3 (tendency towards hazardous eruption) to Level 2 (moderate level of unrest).

Phivolcs said volcanic earthquakes generated by magma extrusion and degassing and occasional rock-fracturing beneath the edifice have decreased from a monthly average of 11 events per day last month to nearly 0 events per day in the first week of December.

Also, recorded rockfall and pyroclastic density currents or PDCs have significantly decreased from monthly averages of 122 to 87 events per day and five to two events per day, respectively, between October and November 2023 to virtually 0 events per day in the first week of December.

«These decreases indicate that magma supply to the summit crater has significantly diminished, resulting in the cessation of lava effusion from the crater and lava collapse-driven rockfall and PDC activity,» Bacolcol said.

Visual and camera monitoring of the volcano's edifice HAS has recorded lessening incandescence of its summit crater and lava flow deposits since last week of November.

As to the ground deformation and microgravity parameters, the Phivolcs chief said there were indications that pressurization of Mayon edifice has abated in the past month.

«But the edifice remains generally pressurized (inflated) due to magma intrusion that has been transpiring since the onset of unrest in June 2023,» he stressed.

On sulfur dioxide (SO2) gas emission, Phivolcs said Mayon peaked at an average of 4, 756 tons per day on Aug. 16, 2023 and «has since been decreasing and increasing in cycles of generally lessened peaks.»

The overall weakening of SO2 emission indicates that volcanic gas from lava exposed on the crater and slopes of Mayon and from magma stored within the volcano is