LEGAZPI CITY, Philippines – Tourists and mountaineers are still prohibited from climbing Mayon Volcano’s crater although other activities on the slopes are allowed after the Philippine Institute of Volcanology and Seismology (Phivolcs) downgraded the alert level from two to one yesterday.
In an advisory issued at 9 a.m., Phivolcs said there has been a decrease in the volcano’s abnormal activities – volcanic quakes, ground deformation, gas emission and crater glow – in the past months.
Albay Gov. Joey Salceda probihited tourists and mountaineers from climbing the crater due to the threat of a sudden eruption.
Ed Laguerta, Phivolcs resident volcanologist, said they recorded only one volcanic quake in the past 24 hours.
Laguerta said there was moderate emission of white steam plumes and the summit was visible last night but no crater glow was observed.
“Precise leveling surveys conducted on Aug. 25 to 30 showed a very slight deflation of the edifice compared in July,” said Laguerta.
Alert level 1 means the volcano is still abnormal.
Laguerta said for the past six months, seismic activity has declined to a daily average of one volcanic quake due to rock fracturing beneath the edifice and occasional rock fall.
Rockfall events were likely initiated by intense rainfall or extreme winds over the volcano summit rather than lava extrusion.
There has no recorded occurrence of low frequency earthquakes associated with magma or volcanic gas movement, he said.