MANILA, Philippines – Just three days after placing Mayon Volcano under Alert Level 2, state volcanologists raised Alert Level 3 for the volcano in Albay province on Thursday, June 8.

Alert Level 3 means there is an “increased tendency towards a hazardous eruption,” coming from the “increasing unrest” under Alert Level 2, which had been declared only last Monday, June 5.

“Mayon is exhibiting magmatic eruption of a summit lava dome, with increased chances of lava flows and hazardous PDCs (pyroclastic density currents) affecting the upper to middle slopes of the volcano and of potential explosive activity within weeks or even days,” warned the Philippine Institute of Volcanology and Seismology (Phivolcs) in a bulletin on Thursday.

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Since Monday, “repeated collapse of the growing summit dome of Mayon Volcano has generated an increasing number and volume of rockfall events,” according to Phivolcs.

There were 267 rockfall events and 2 volcanic earthquakes from June 5 to 8, compared to 54 rockfall events from June 1 to 4.

“These events had durations of 1 to 3 minutes and transported lava debris within a kilometer range of the southern upper slopes” of Mayon Volcano, said Phivolcs.

The agency added that there were 3 PDC events lasting 4 to 5 minutes at 6:18 am, 9:53 am, and 11 am on Thursday. PDCs are made up of fragmented volcanic particles, gases, and ash that travel down volcanic slopes at high speeds.

Mayon’s southeastern middle and upper slopes have also been inflated or swollen since February.

But so far, sulfur dioxide emission remains low, “at baseline or background levels.”

“The overall monitoring parameters indicate that very slow extrusion of shallow degassed magma is ongoing and is incrementally increasing in rate,” or an “effusive magmatic eruption is taking place,” Phivolcs said.

State volcanologists recommended that evacuation be enforced in the 6-kilometer-radius permanent danger zone surrounding Mayon Volcano. The Albay provincial government will implement the evacuation.

Potential hazards include PDCs, lava flows, rockfalls, ashfall, and lahar.

“Based on the current prevailing wind pattern, ashfall events may most likely occur on the south side of the volcano,” Phivolcs said.

Pilots should also avoid flying close to Mayon Volcano’s summit. – Rappler.com