Mayon records 2nd-highest sulfur dioxide emission since July

Mayon Volcano is seen spewing an ash plume 150 meters tall at 9:08 a.m. on Friday, Aug. 28, 2026. - Screengrab from Phivolcs MANILA, Philippines - Mayon Volcano recorded its second-highest sulfur dioxide (SO2) emission since volcanic gas concentrations began declining in July, prompting state seismologists on Friday to warn of the possibility of renewed eruptive unrest.

In an advisory, the Philippine Institute of Volcanology and Seismology (Phivolcs) said SO2 emissions from Mayon's summit crater reached 8,165 tonnes per day on Thursday, based on averaged measurements from stationary ultraviolet spectrometry.

This was significantly higher than the volcano's average SO2 emission of 4,196 tonnes per day since its alert status was lowered to Alert Level 2 on Aug. 5.

The increase was accompanied by a slight rise in low-frequency volcanic earthquakes (LFVQs), which Phivolcs attributed to volcanic degassing.

READ: Mayon sulfur emissions spike raises eruption concern