Mayon lava flows don’t threaten residential areas, aerial survey shows

By Celso Amo
The Philippine Star - August 7, 2006

LEGAZPI CITY — Lava flowing down the slopes of Mayon Volcano is contained in two major channels and does not pose a threat to populated areas in two barangays here, an aerial survey showed.

Top officials of the provincial disaster management office and the Philippine Institute of Volcanology and Seismology (Phivolcs) surveyed the extent of the advancing lava flows on board a Huey helicopter yesterday morning.

In a briefing attended by Albay Gov. Fernando Gonzales, Ed Laguerta, Phivolcs’ resident volcanologist, said the lava flows do not threaten the residential areas in Barangays Mabinit and Bonga because they are contained in the Mabinit and Bonga channels on the volcano’s western and eastern flanks.

Laguerta told The STAR that the Mabinit and Bonga channels "act as natural buffer zones for the flowing lava."

After 23 days of continuous lava flows, Mayon has already extruded an estimated 19 million to 20 million cubic meters of hot, molten rocks, or about 1.9 million cubic meters per day, Laguerta said.

Phivolcs said the lava has already spilled into the Bonga gully, east of the Mabinit channel.

Based on the aerial survey, the lava flowing to the Mabinit channel has spanned for more than 6.1 aerial kilometers from Mayon’s crater at an elevation of 269 meters.

The lava slowly descending toward the general direction of the Bonga channel, on the other hand, was estimated at about 5.1 aerial kilometers from the crater at an elevation of 320 meters.

In a bulletin, Phivolcs said some lava blocks have reached the gullies facing Miisi in Daraga and Buyoan this city.

Seismic sensors detected 371 tremor episodes caused by the lava blocks tumbling down the slopes of Mayon.

Twelve volcanic earthquakes were also detected, signifying the ascent of magma inside the volcano’s vent.

Sulfur gas emission dropped to 1,919 tons last Saturday from 2,965 tons the previous day.

Cedric Daep, head of the Albay provincial disaster management office, said their contingency plans remain in place even if the lava flows pose no immediate threat to the residential areas in Barangays Mabinit and Bonga.