Mayon volcano. Photo courtesy of Camalig Information Office.
Mayon Volcano is showing fresh signs of unrest after sulfur dioxide emissions surged to their second-highest level since mid-July, raising the possibility of renewed eruptive activity at its summit.
The Philippine Institute of Volcanology and Seismology said Tuesday that Mayon emitted an average of 7,115 tonnes of sulfur dioxide per day, nearly double the 3,844-tonne daily average recorded since the volcano was downgraded to Alert Level 2 on Aug. 5.
The spike in volcanic gas was accompanied by a slight increase in low-frequency volcanic earthquakes, which Phivolcs associates with degassing. Twelve such earthquakes were recorded, although real-time seismic energy release remained at background levels.
Adding to the signs of unrest, monitoring instruments detected short-term swelling or pressurization along the northern and eastern sectors of Mayon.
Phivolcs said the combination of increased gas emissions and other monitoring indicators could signal a shift toward renewed eruptive activity at the summit crater.
Despite the developments, Mayon remains under Alert Level 2, indicating moderate unrest. Phivolcs, however, warned of the possibility of recurring eruptive unrest and advised communities to remain prepared should conditions escalate.
Entry into the six-kilometer Permanent Danger Zone remains prohibited. Local governments and communities within identified pyroclastic density current hazard zones were advised to prepare for a possible escalation to Alert Level 3.
Phivolcs also warned of lahars and sediment-laden flows during sustained heavy rains and advised pilots to avoid flying close to Mayon’s summit because sudden eruptions could produce hazardous ash and ballistic fragments.