The Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Saturday reported that Mayon Volcano recorded a total of 338 rockfall events and 72 pyroclastic density currents (PDCs) over the past 24 hours, based on monitoring data from 12:00 a.m. on 16 January to 12:00 a.m. on 17 January.
PHIVOLCS said Mayon remains under Alert Level 3 due to intensified unrest, noting ongoing magmatic activity, including lava dome growth and lava flow effusion at the summit.
The agency also observed crater glow visible to the naked eye. During the 24-hour monitoring period, Mayon emitted 4,970 tonnes of sulfur dioxide, while obscured plumes were observed throughout the day.
PHIVOLCS warned the public of possible hazards, including rockfalls, landslides or avalanches; ballistic fragments; lava flows and lava fountaining; pyroclastic density currents; moderate-sized explosions; and lahars during heavy and prolonged rainfall.
The agency reiterated that entry into the six-kilometer Permanent Danger Zone is strictly prohibited, and cautioned against entering the Extended Danger Zone without vigilance. It also advised against flying aircraft close to the volcano.
Earlier, the Office of Civil Defense said additional precautions are necessary in Albay as Mayon remains in unrest, warning that adverse weather conditions could worsen the situation.
“Given the ongoing unrest of Mayon Volcano in Albay, additional measures are needed, as Tropical Storm Ada may exacerbate the emergency situation in the province,” Civil Defense Administrator and Undersecretary Harold Cabreros said on Friday night.
PHIVOLCS also reported that on Friday, monitoring instruments detected increased seismic energy and volcanic gas release from Mayon.
The agency said three of the volcano’s 16 monitoring stations recorded a spike in real-time seismic amplitude measurement (RSAM) between Thursday and Friday, despite the absence of recorded volcanic earthquakes. RSAM levels returned to zero record on Saturday.
“This increase was induced by a higher rate of rockfall and pyroclastic density current (uson) activity, which indicates a rise in the rate of lava effusion at the summit crater of Mayon,” PHIVOLCS said in its advisory issued Friday.