Magma up in Mayon

LEGAZPI CITY — Government volcanologists said that fresh magma deposit is rising towards the summit, which is responsible for vigorous lava extrusions and rockfalls during the past week.

"Fresh magma is now rising towards the summit," Phivolcs scientist Ernesto Corpuz told The STAR during a telephone interview after a team of scientists had conducted an aerial survey to assess the crater of the Mayon Volcano.

Corpuz added that the present Alert Level 3 is maintained because the lava outflow is still within the six-kilometer permanent danger zone.

"But if there is sudden eruption, then we can immediately raise the present alert level to 4," Corpuz explained.

Phivolcs bulletin said rockfalls, small lava avalanches and moderate steam emission dominated the activity of Mayon Volcano which is in a mild stage of eruption during the past 24 hours.

The lava fragments also caused continuous episodes of rockfalls which produced a distinct ground tremor of high frequency spectra.

Seismic network recorded 18 low frequency volcanic earthquakes and 82 high frequency short duration harmonic tremors related to rockfalls.

Phivolcs said that recordings of multiple rockfall events from the reference station in Upper Anoling (in Camalig) grade into each other, which means that there are actually more vigorous extrusions and rockfall events that those recorded by this station," the bulletin said.

Falling detached lava blocks were observed from 7 p.m. Friday to 5 a.m. yesterday, disintegrating upon impact into bright glowing boulders as it descends along the Bonga Gully at night. Also, bright crater glow was observed from 7 p.m. Friday to 5 a.m. yesterday.

"There were more volcanic earthquakes for this observation period than the previous days while low frequency type earthquakes, which probably reflect magma ascent, have increased to 18 compared to 8 during the previous recording," Phivolcs’ latest bulletin said. — Celso Amo