Phivolcs raises Taal alert to ‘2,’ warns of eruption

source: gma

Citing at least four disturbing recent trends indicating an eruption, state volcanologists on Saturday raised the alert level at Taal Volcano in Batangas to “2."


The Philippine Institute of Volcanology and Seismology (Phivolcs) said an eruption is possible as there are signs of magma rising to the surface.

“In view of the above observations at Taal Volcano and the interpretation that magma has been intruding towards the surface, as manifested by (carbon dioxide) being released in Main Crater Lake and the increase in seismic activity, Taal Volcano’s status is now raised to Alert Level 2. With this alert status, the present activities could eventually lead to an eruption," it said in its website.

With the raising of the alert level, Phivolcs advised the public that the Main Crater, Daang Kastila Trail and Mt. Tabaro are strictly “off limits."

Mt. Tabaro was the site of an eruption in 1965, it noted.

Phivolcs pointed out sudden hazardous steam-driven explosions may occur and high concentrations of toxic gases may accumulate in those areas.

In raising the alert level, Phivolcs noted “significant changes" as indicated by the following observations:
1. Seismic activity at Taal Volcano continued to worsen, as the number of volcanic earthquakes detected gradually rose and the depths of the plotted quakes are becoming shallow (1 to 4 km).

There is also an increase in the number of perceptible quakes. During the past 24 hours, two quakes were felt at the Volcano Island with Intensities ranging from II to III and one of them was accompanied by rumbling sounds.

At least 21 volcanic quakes were detected by the seismic network for the past 24 hours.

2. Gas measurements conducted at Taal Main Crater Lake yielded carbon dioxide emission flux of 1,875 tons per day (t/d) in February 2011 and 4,670 t/d during the last week of March 2011. The remarkable increase in carbon dioxide concentration indicates its release from the magma at depth.

3. Ground deformation survey (precise leveling) conducted around the Volcano Island this week showed that volcano edifice is still inflated as compared with February 2011 survey.

4. Steaming activities at the northern and northeast sides of the Main Crater occasionally intensified. Sometimes, intensification of steaming activity is accompanied by audible hissing sounds.

Phivolcs also reiterated its warning that breathing air with high concentration of carbon dioxide can be lethal to humans and animals, and can damage vegetation.

It likewise reiterated the entire Volcano Island is a Permanent Danger Zone (PDZ), and permanent settlement in the island is strictly not recommended.
Bulusan, Mayon still at alert level 1

Phivolcs said Bulusan Volcano in Sorsogon and Mayon Volcano in Albay remain under Alert Level 1.

It said Bulusan had at least two volcanic earthquakes during the past 24 hours.

Entry to Bulusan’s 4-km radius PDZ is strictly prohibited, since the area is at risk to sudden steam and ash explosions.

“Due to the prevailing wind direction, residents in the northwest and southwest sectors of the volcano are reminded to take precautions against ash-falls," it said.

“Furthermore, people living near valleys and river/stream channels should be vigilant against sediment-laden stream flows and lahar in the event of heavy and prolonged rainfall," it added.

As for Mayon, Phivolcs detected two rockfall-related events during the past 24 hours while steam emission varied from wispy to moderate and drifted towards the southwest direction.

Fair crater glow (Intensity II, can be seen by the naked eye) was observed Friday night.

“Although this means that no eruption is imminent, it is recommended that the public should not enter the 6-km PDZ due to the continuing threat from sudden small explosions and rockfalls from the upper and middle slopes of the volcano. Active stream/river channels and those perennially identified as lahar prone areas in the southern sector should also be avoided especially during bad weather conditions or when there is heavy and prolonged rainfall," it said.

source: gma