LEGAZPI CITY, Albay: The country’s most active volcano, Mount Mayon was exhibiting faint crater glow again three years after it erupted.
The crater glow has been observed for three weeks now, starting on Jan. 6, 2021 with the second sighting on Jan. 8, 2021 and the latest sighting on Thursday night as it also registered 10 low-frequency volcanic earthquakes.
A crater glow is an indication that magma beneath the volcano crater is rising, which could lead to possible explosion.
Mt. Mayon last blew its top on Jan. 22, 2018 with alert level 4 (hazardous eruption imminent), raised by the Philippine Institute of Volcanology and Seismology (Phivolcs) at the time.
The volcano has erupted more than 50 times in the past 500 years.
It is one of the Philippines’ 22 active volcanoes.
The sighting of the crater glow has prompted Phivolcs to prohibit the public from staying within a six-kilometer permanent danger zone as a precaution.
Ten volcanic earthquakes were felt during a 24-hour observation period on Thursday.
Moderate emission of white steam-laden plumes that crept down the slopes before drifting to the north was also observed.
The faint crater glow from the summit could be seen at night.
On Dec. 29, 2020, sulfur dioxide emission was last measured at an average of 676 tons per day, which was higher than the normal status of the volcano.
Ground deformation data from leveling surveys, taken from Nov. 23, 2020 to Dec. 3, 2020, indicated slight deflation of the slopes compared to data taken in October 2020.
Electronic data showed short-term deflation of the middle slopes starting in July 2020 after a period of nonsteady inflation from late 2019 to mid-2020.
Continuous, global-positioning-satellite data recorded longer-term inflation of the lower to middle slopes since July 2019.
Phivolcs said as of Thursday, Mayon Volcano was at alert level 1, which means that it is in an abnormal condition.
“Although this means that at present, no magmatic eruption is imminent, it is strongly advised that the public refrain from entering the 6-kilometer radius permanent danger zone due to the perennial life-threatening dangers of rockfalls, landslides/avalanches at the middle to upper slopes, sudden ash puffs and steam-driven or phreatic eruptions from the summit,” it added.
Active stream or river channels and those identified as perennially lahar-prone areas in all sectors of the volcano should also be avoided, especially during extreme weather conditions when there is heavy and prolonged rainfall, according to Phivolcs.