LEGAZPI CITY, Philippines—The Philippine Institute of Volcanology and Seismology has advised residents of places experiencing ash fall following a phreatic explosion at from Mayon Volcano in Albay province to stay indoors.
An ash column of up to 500 meters was seen toward the southwest of the volcano, and ashes had fallen on the village of Muladbucad in Guinobatan town, according to Alex Baloloy, science research specialist of Philvocs in Legazpi city.
Some ash fall was reported also in the towns of Oas and in Ligao City.
Baloloy stressed that Mt. Mayon did not explode and that no volcanic eruption was imminent, thus the alert status around the volcano remained at normal level. What happened, he said, were ‘small’ ash explosions, including small steam ash ejections.
Still, Baloloy advised the public not to venture into the six-kilometer danger zone around the volcano’s crater. Three groups of mountaineers, numbering about 20 persons, were on a trek on Mayon when the phreatic explosion occurred and some of them were reported killed or injured.
A volcanologist at the Phivolcs office in Manila said in a radio interview a phreatic explosion could be triggered by a buildup of gas which, when it explodes, could send volcanic ash deposited on the volcano’s rim shooting into the sky, or by rainwater seeping into the volcano and coming in contact with smoldering volcanic material.
Meanwhile, aviation authorities in Legazpi declared the area around Mt. Mayon a no-fly zone and ordered the cancellation of all flights at the Legazpi City Airport, which is located at the foot of the volcano.