PHIVOLCS: Increased SO2 emission from Mayon Volcano may be sign of renewed eruptive activity

There is an increase in volcanic SO2 emission from Mayon Volcano on Monday, August 17, 2026 that could be a forewarning of renewed eruptive activity, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported.

PHIVOLCS said the volcanic sulfur dioxide or SO2 gas emission from the summit crater of Mayon Volcano reached a very high emission rate of 8,393 tonnes/day based on averaged measurements by campaign UV spectrometry.

"This is the highest emission from Mayon recorded since volcanic gas concentrations began decreasing on 16 July 2026," the agency added.

SO2 gas emission - since the volcano’s status was lowered to Alert Level 2 on August 5, 2026 - averaged only 2,532 tonnes/day.

"The abrupt rise follows a short-term trend of swelling or pressurization of the northern and eastern sectors of the volcano edifice recorded by electronic tilt deformation stations of the Mayon Volcano Network," PHIVOLCS said.

Volcanic seismicity and real-time seismic energy release has remained in the background levels.

Elevated volcanic SO2 emissions, state volcanologists said, could forewarn of a potential shift to renewed eruptive activity at the summit crater that could generate volcanic hazards all around the volcano, the impacts of which can be worsened by the prevailing poor weather conditions.

Mayon Volcano remains under Alert Level 2 or moderate level of unrest, said PHIVOLCS, adding that there are currently new possibilities of eruptive unrest recurring.

"A new phase of eruption could generate life-threatening volcanic hazards that include pyroclastic density currents (PDCs) or uson, rockfall, ballistic fragments that can be thrown out as projectiles from the crater and extensive ashfall that could severely impact communities downwind of the volcano," the agency said.

The public was advised to remain vigilant and must refrain from entering the 6-kilometer radius Permanent Danger Zone (PDZ).

Communities and local government units within the pre-determined zones of PDC hazards, meanwhile, must prepare and be ready to respond in case activity escalates and the alert level is stepped up to Alert Level 3.

"Increased vigilance and pre-emptive response actions to guard against lahars and sediment-laden streamflow along channels draining the edifice are also advised during sustained heavy or intense rains especially in the event of simultaneous explosive eruption," said PHIVOLCS.

"Civil aviation authorities should continue to advise pilots to avoid flying close to the volcano’s summit as ash and ballistic fragments from any sudden eruption can be hazardous to aircraft," the agency also said, adding that it continues close monitoring of Mayon Volcano and that any new development will be communicated to all concerned stakeholders. — BAP, GMA News