Lava flows, pyroclastic density currents (PDCs), rockfalls, and intermittent ash emissions continued to be observed at Mayon Volcano on the 120th day of its effusive eruption on Tuesday, May 5, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.

A brief collapse of lava on the southwestern slopes of Mayon Volcano generated a PDC or “uson,” that was observed between 7:19 a.m. and 7:26 a.m. on Tuesday.

On May 2, a stronger episode was recorded when a PDC accompanied by ash fall spread to several communities in Albay.

Phivolcs Director Teresito Bacolcol said the activity remains consistent with an effusive eruption under Alert Level 3, indicating that current conditions are still within expected parameters.

The volcano has been under Alert Level 3, or intensified unrest, since January 6.

“Ang posibilidad [ng eruption] ay laging nariyan kasi nasa Alert Level 3 pa rin ang Mayon Volcano. Anything can happen depende sa pinapakitang parameters, pero sa ngayon, lahat ng pinapakita niya ay consistent pa rin sa alert level niya (The possibility of eruption is always there because Mayon Volcano remains under Alert Level 3. Anything can happen depending on the parameters being observed, but for now, all indicators remain consistent with its current alert level),” Bacolcol said in a televised briefing on Monday, May 4.

He said monitoring data show no indication yet of escalation.

He added that the current pattern is similar to the 2023 eruption.

“This is following the 2023 template, ganun rin naman yung pinapakita effusive eruption hanggang Alert Level 3 lamang noong 2023. Hindi natin ito inescalate to Level 4 (This follows the 2023 template; the effusive eruption also remained at Alert Level 3 in 2023. We did not escalate this to Level 4),” Bacolcol said.

An effusive eruption is characterized by the slow outflow of lava from the volcano, forming rivers of molten rock rather than explosive blasts.

“Hindi pa natin tinataas sa Alert Level 4 dahil based on available data consistent pa rin ang activity sa Alert Level 3, bagamat delikado pa rin ito (We have not raised it to Alert Level 4 because based on available data, activity remains consistent with Alert Level 3, although it is still dangerous),” he added.

Bacolcol said the 2023 eruption lasted about six months, from June to December 2023, before it was downgraded from Alert Level 3 to Alert Level 2.

“Itataas lang natin yung alert level if we observe clear and sustained escalation, more widespread and higher volumes of ‘uson’, sustained lava fountaining, stronger explosions, increased seismicity, and significant changes sa gas emissions at ground deformation (We will only raise the alert level if we observe clear and sustained escalation, more widespread and higher volumes of ‘uson,’ sustained lava fountaining, stronger explosions, increased seismicity, and significant changes in gas emissions and ground deformation,” he explained.

Bacolcol said that if Alert Level 4 is raised, authorities should be ready for evacuation of residents beyond the six-kilometer Permanent Danger Zone.