LEGAZPI CITY, Albay: Mayon Volcano recorded a ground swelling of three millimeters during the past 10 days based on the latest ground deformation survey of the Philippine Institute of Volcanology and Seismology (Phivolcs) geodetic team.

Phivolcs resident volcanologist Ed Laguerta on Thursday said that although the volcano appears to be calm and there have been less earthquakes and rockfall events in the almost one-week period, their instruments have recorded a continuous inflation of the ground and an increase in the volume of sulfur dioxide (SO2) emission.