Ruby may trigger lahar flow – Phivolcs

LEGAZPI CITY, Philippines – Heavy rains over the Bicol region due to Typhoon Ruby could trigger lahar flow from volcanic materials on the slopes of Mayon Volcano in Albay and Bulusan Volcano in Sorsogon.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said extreme rainfall in Albay could result in landslides and erosion of pyroclastic deposits on the slopes of Mayon.

“Potentially large-magnitude lahar can threaten downstream communities along river channels with inundation, burial and washout,” according to Phivolcs’ latest lahar bulletin.

Phivolcs said at risk are the communities along the river channels of Masarawag and Maninila in Guinobatan, Buyuan-Padang and Mabinit in Legazpi City, Lidong and Basud in Sto. Domingo, Miisi in Daraga, Anoling in Camalig and Nabonton in Ligao City. 

Lahar-related flooding, washout and siltation also threaten Yawa River and low-lying areas in Legazpi City.

In Sorsogon, Phivolcs said moderate-volume lahar threatens communities along the Malunoy, Mapaso, Cadac-an, Tinampo and Cogon Rivers in Irosin town and the Añog-Rangas River in Juban.

Phivolcs appealed for vigilance among residents of lahar-threatened communities.

Cedric Daep, chief of the Albay Public Safety and Emergency Management Office, said they are considering moving Mayon evacuees out of the evacuation centers if they would be affected by lahar flow.