Mayon volcano. Photo courtesy of Camalig Information Office.
The Philippine Institute of Volcanology and Seismology (Phivolcs) warned communities near Mayon Volcano to avoid river channels after a muddy flow believed to be lahar was observed in Daraga, Albay.
A resident recorded the flow rushing through the Mi-isi Channel on Thursday, July 16, after volcanic deposits on the upper slopes were apparently washed downstream.
Phivolcs Volcano Monitoring and Eruption Prediction Division chief Ma. Antonia Bornas said the material was likely lahar that became diluted as it reached lower areas.
She said smaller flows had been gradually removing loose deposits trapped in channels, but prolonged or intense rainfall could trigger larger and more dangerous lahars.
Volcanic ash and debris had accumulated as far as 5.4 kilometers along the Binaan Channel following a major lava collapse at the Mi-isi Gully on May 2.
Daraga Mayor Victor Perete said deposits in some areas near an all-terrain vehicle site in Barangay Mi-isi had reached more than 50 meters deep, prompting calls to clear and deepen the channel.
Perete said desilting could help keep future flows within their present path and reduce the risk of volcanic debris spilling toward nearby communities.
Local officials advised residents to stay away from the Binaan River and the six-kilometer Permanent Danger Zone as village watchmen monitored the area amid intensified eruptive activity at Mayon.