Manila: The Philippine Institute of Volcanology and Seismology (Phivolcs) bared on Friday an increase in sulfur dioxide (SO2) emissions from Mayon Volcano to 8,165 tonnes per day on Thursday, the second-highest level since volcanic gas concentrations began decreasing on July 16.
According to Philippines News Agency, the elevated SO2 emissions could forewarn of a potential shift to renewed eruptive activity at the summit crater, which could generate volcanic hazards around the volcano. Phivolcs warned that prevailing poor weather conditions could worsen the impacts of such hazards.
A new phase of eruption could generate life-threatening hazards, including pyroclastic density currents (PDCs), rockfalls, ballistic fragments, and heavy ashfall that could affect communities downwind of the volcano. The agency said the very high SO2 emission was based on averaged measurements from stationary ultraviolet (UV) spectrometry. Since Mayon's status was lowered to Alert Level 2 (moderate level of unrest) on Aug. 5, its SO2 emission has averaged 4,196 tonnes per day.
Phivolcs said the abrupt increase in volcanic gas emission was accompanied by a slight increase in the occurrence of low-frequency volcanic earthquakes (LFVQs), which is attributed to volcanic degassing. The Mayon Volcano Network also recorded a total of four LFVQs. However, the agency said real-time seismic energy release remained at background levels.
A short-term trend of swelling or pressurization was also observed in the northern and eastern sectors of the volcano edifice, based on measurements from electronic tilt deformation stations of the Mayon Volcano Network. Phivolcs reiterated that Mayon remains under Alert Level 2 but noted there are currently new possibilities of recurring eruptive unrest.
The public was reminded to refrain from entering the six-kilometer Permanent Danger Zone (PDZ) around the volcano. Communities and local government units within predetermined PDC hazard zones were also advised to prepare and be ready to respond in case volcanic activity escalates and the alert status is raised to Alert Level 3.
The agency also urged communities to take preemptive measures against lahars and sediment-laden streamflows along channels draining the volcano, particularly during sustained heavy or intense rains and in the event of a simultaneous explosive eruption. Phivolcs said it continues to closely monitor Mayon Volcano and will communicate any new developments to concerned stakeholders.
