LEGAZPI CITY, Philippines – After a short lull, Mayon volcano became restive again yesterday, with volcanologists detecting several volcanic earthquakes and high sulfur dioxide emission.
In its latest bulletin, the Philippine Institute of Volcanology and Seismology (Phivolcs) said at least 27 volcanic earthquakes were recorded yesterday, compared to none the previous day, while sulfur dioxide emission was measured at 2,153 tons, or more than four times the normal 500 tons per day.
Ted Sandoval, Phivolcs spokesman, said the sudden increase in tremors signifies that magma movement inside the volcano has resumed, while the high sulfur dioxide volume means massive degassing is going on.
“Probably the tremors were due to the fresh magma being pushed through gaseous pressure inside the volcano’s chamber,” Sandoval told The STAR in a phone interview.
Sandoval said volcanic quakes usually occur when magma is being pushed toward the crater through pressure from degassing.
He, however, said these abnormal signs are not yet enough to warrant an increase in the alert level around Mayon from 2 to level 3.
Volcanologist Helma Canon, who is based at Phivolcs’ Lignon Hill Observatory, said 15 of the tremors were low frequency, and the rest, high frequency.
Sandoval another proof of magma being pushed toward the crater is the ground deformation observed at the slopes of Mayon, varying from four to 10 millimeters.