Heavy rains trigger lahar flow at Anoling Channel

February 19, 2018

By Celso Amo

LEGAZPI CITY --- The Philippine Institute of Volcanology (Phivolcs) said heavy rains spawned by tropical storm Basyang triggered lahar at Anoling Channel.

Ed Laguerta, Mayon resident volcanologist, said the lahar was confined at the Anoling Channel while pyroclastic density currents were also spawned by the heavy rains at other channels and at the Miisi, Bonga and Basud Gulllies.

Laguerta said about 15.5 million cubic meters of pyroclastic density currents are now deposited at the gully and river channels at Quirangay, Miisi, Mabint, Buyuan, Matanag, Basud and at the northern channels.

Pyroclastic density currents or PDCs due to Mayon’s continuing eruption have deposited at gullies at Miisi (4.6 million cubic meters), Bonga (4.5 million cubic meters) and 4.2 million cubic meters at Basud.

“We are now coordinating with the different city and municipal disaster risk reduction and management officers of Daraga, Camalig, Guinobatan, Ligao City, as well as of Bacacay, Sto. Domingo, and Tabaco City to measure up the volume of possible lahar deposits for evacuation response,” said Cedric Daep, Albay provincial security and emergency management office(APSEMO) head.

“Our long term threat is now lahar when all those pyroclastic density currents from the slope of Mayon are slowly brought down by heavy rains,” Daep added.

Daep said Apsemo is closely monitoring the rainfall level despite the assurance of the Philippine Atmospheric Geophysical and Astronomic Services Administration (PAGASA) here that the rainfall level tropical storm Basyang triggers will not be heavy and torrential.

Lahar can also be triggered during thunderstorm with its accompanying heavy rains.

Legazpi City Mayor Noel Rosal also said that he is going to evacuate more than 1,000 villagers, mostly fishermen from Sitio Tinago, due to lahar threat in Barangay Bigaa when heavy rains start due to tropical storm Basyang.

Meanwhile, Mayon’s activity in the past 24 hours was characterized by sporadic and weak lava fountaining, lava flow and degassing from the summit crater.

Although the upper slopes were heavily obscured, the seismic record indicates discrete episodes of lava fountaining that lasted five to fifty minutes.

Throughout the night, lava flows and consequent incandescent rockfalls were observed in the Miisi and Bonga-Buyuan channels.

Effused volumes of incandescent lava flows have advanced to 3.3 kilometers, 4.5 kilometers and 900 meters down the Miisi, Bonga and Basud Gullies from the summit, respectively.

A total of ninety-four volcanic earthquakes, most of which corresponded to lava fountaining events were recorded by Mayon’s seismic monitoring network.

Civil aviation authorities have been sked to advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft.




 

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