Mayon: The sulfur dioxide (SO2) emission of Mayon Volcano surged to 8,393 tons per day on Aug. 17, prompting the Philippine Institute of Volcanology and Seismology (Phivolcs) to warn of possible renewed eruptive unrest. In a bulletin on Tuesday, Phivolcs recorded seven volcanic earthquakes. Crater glow was faint but visible to the naked eye, while the plume was obscured.
According to Philippines News Agency, lava continued to flow through different gullies on Basud (3.8 km), Bonga (3.2 km), and Mi-sis (2.7 km). In an advisory issued at 10:30 p.m. Monday, Phivolcs said the latest SO2 reading was based on averaged measurements from campaign ultraviolet spectrometry. The latest reading was the highest recorded since volcanic gas concentrations began declining on July 16.
Since Mayon's status was lowered to Alert Level 2, or a moderate level of unrest, on Aug. 5, its SO2 emissions have averaged only 2,532 tonnes per day. Phivolcs said the abrupt increase in volcanic gas emission followed a short-term trend of swelling or pressurization in the northern and eastern sectors of the volcano edifice, as recorded by electronic tilt deformation stations of the Mayon Volcano Network.
Despite the increase in SO2 emission, volcanic seismicity and real-time seismic energy release remained at background levels. Phivolcs, however, warned that elevated volcanic SO2 emissions could forewarn a potential shift to renewed eruptive activity at the summit crater, which could generate volcanic hazards around the volcano. Prevailing poor weather conditions could worsen the impacts.
A new phase of eruption could generate life-threatening hazards, including pyroclastic density currents (PDCs), or "uson," rockfalls, ballistic fragments, and extensive ashfall, which could severely affect communities downwind of the volcano. Phivolcs reminded the public to strictly avoid entering the six-kilometer Permanent Danger Zone (PDZ) around Mayon.
Communities and local government units within predetermined areas exposed to PDCs were also urged to remain prepared and ready to implement response measures should volcanic activity intensify and the alert level be raised to Alert Level 3. The agency likewise advised increased alertness and preemptive measures against lahars and sediment-laden streamflow along channels draining the volcano, particularly during sustained heavy or intense rains and in the event of a simultaneous explosive eruption.
Civil aviation authorities were also advised to continue warning pilots against flying close to the volcano's summit, as ash and ballistic fragments from any sudden eruption could pose hazards to aircraft.
