The Office of Civil Defense on Saturday urged residents near Mayon Volcano and Kanlaon Volcano to remain alert after both volcanoes showed signs of renewed activity, including pyroclastic density currents and ash emissions.

The agency advised residents, particularly those in Negros Oriental and Negros Occidental, to take precautions against possible ashfall following an ash emission from Kanlaon at about 1:49 p.m.

In an interview with the DAILY TRIBUNE, Kanlaon Volcano Observatory resident volcanologist Mari-Andylene Quintia confirmed the activity.

“Yes. There was an ash emission earlier at 1:49 p.m. No visual observation was recorded, but seismic and infrasound signals were detected,” Quintia said.

According to the Philippine Institute of Volcanology and Seismology,(Phivolcs)Mayon generated rockfall and pyroclastic density current events at about 11:20 a.m., while Kanlaon emitted ash at 1:49 p.m.

Pyroclastic density currents are fast-moving flows of hot volcanic gas, ash and rock fragments that can pose serious hazards near a volcano’s slopes.

Phivolcs’ latest 24-hour monitoring report showed that Mayon recorded two weak strombolian eruptions, 364 rockfall events, 24 volcanic earthquakes and nine volcanic tremors.

Kanlaon, meanwhile, generated seven ash emission events lasting between eight and 60 minutes, along with 16 volcanic earthquakes and 12 volcanic tremors.

Both volcanoes remain under alert status. Mayon is under Alert Level 3, indicating a relatively high level of unrest, while Kanlaon remains under Alert Level 2.