Mayon gas surge signals possible renewed eruption

By Jordan Domingo

LEGAZPI CITY --- Mayon Volcano could be heading toward renewed eruptive activity following a sharp surge in sulfur dioxide (SO₂) emissions that reached 8,393 tonnes per day on Monday, the highest level recorded since volcanic gas concentrations began declining in July.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said the abrupt increase in volcanic gas emissions could signal a shift toward renewed eruption at the summit crater, potentially generating hazardous conditions around the volcano.

The warning comes less than two weeks after Mayon’s alert status was lowered to Alert Level 2, or moderate unrest, from Alert Level 3, or intensified unrest, on Aug. 5.

Since the alert level was downgraded, SO₂ emissions have averaged 2,532 tonnes per day. The latest reading represents a substantial increase from that average.

Phivolcs said the surge in emissions followed a short-term trend of swelling or pressurization in the northern and eastern sectors of the volcano edifice.

Volcanic seismicity and real-time seismic energy release have also been detected in the background, the agency said.

“Elevated volcanic SO₂ emissions could forewarn of a potential shift to renewed eruptive activity at the summit crater,” Phivolcs said, warning that the resulting hazards could be aggravated by prevailing poor weather conditions.

These hazards include pyroclastic density currents, or uson; rockfalls; ballistic fragments ejected from the crater; and extensive ashfall that could severely affect communities downwind of Mayon.

Phivolcs urged local governments to prepare for a possible escalation of volcanic activity and a return to Alert Level 3.

The 6-kilometer Permanent Danger Zone around Mayon remains off-limits to the public.