Friday, September 02, 2005

Mayon threatens of possible eruption

The Philippine Institute of Volcanology and Seismology (Phivolcs) warned on Wednesday that another round of major eruptions of Mayon Volcano may occur following the magma reactivation and extrusion of lava pile or lava dome within the summit crater.

Ed Laguerta, Phivolcs resident volcanologist chief, said the latest episode of lava accumulation indicates a phase of low-level magmatic activity which might lead to two general scenarios, such as major eruptions and “recharging mode” that a major explosive eruption may occur.

“Mayon’s magma system is reactivating which could lead to another round of major eruptions. The other possible situation is that Mayon is merely in a recharging mode and that a major explosive eruption are some years away, consistent with general and relatively nonviolent periods of activity since the l968 eruption.”

“This notice is a confirmation of lava accumulating within the summit crater. At present the extrusion rate of the lava pile, or lava doom, is very slow and that the volume of lavas is small enough to be contained by the crater,” Laguerta said.

Remy Escobal, 28, resident of Barangay Bogtong, Legazpi City, told The Manila Times that an exodus of snakes from the slopes of Mayon has occured since last month.

“We noticed that several snakes from Mayon’s slope have been found. We also heard successive rumbling sounds of rocks from the volcano especially at nighttime,” Escobal said.

While Marvin Lita, 38, of Barangay Salvacion Daraga, Albay, told The Times that he also noticed a series of minor earthquakes in their area.

Salvacion village is about 7 to 8 kilometer-radius from Mayon.

Two weeks ago, the office of the Public Safety Management and Disaster Office, led by Cedric Daep, and Laguerta conducted an aerial survey and discovered that a lava pile occupies the unusual bowl-like morphology on the crater floor.

The lava pile resulted from slow extrusion of magma following a string of ash explosions that occurred between March and May in 2003.

In October 2003 the Ligñon Hill Observatory in this city reported incandescent glow on the summit indicating that fresh magma had breached the surface.

Phivolcs raised the alert status to Level 2 to reflect the increase in volcanic activity. At least two ash explosions occurred in mid-2004 followed by reports of summit plow.

Since then, Laguerta said that volcano-monitoring equipments consistently recorded more tremors, higher-than-usual sulfur dioxide emissions and slight inflation of the edifice.

If the crater fills up, lavas will spill over to the lowest portion of the crater rim that faces the southeast portion of Mayon.

The growth of the lava dome also increases its instability which may result in a partial collapse of pyroclastic flows that are likely to impact the permanent danger zone.

Extrusion of lavas are sporadic, discrete explosions are also considered to affect the zone.
Laguerta advices the public to keep away from the 6 kilometer-radius of the danger zone.

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