Taal volcano on alert level 2

MANILA -- State volcanologists on Saturday discouraged the public to go near the premises of the restive Taal volcano in Batangas as they upgraded the alert status from 1 to 2.

Philippine Institute of Volcanology and Seismology (Phivolcs) Director Renato Solidum said alert Level 2 indicates unrest probably of magmatic origin and could eventually lead to eruption.

Solidum urged the public to avoid going to the Main Crater, Daang Kastila Trail at the northeastern slope and Mt. Tabaro, which is the site of the 1965 eruption.

These areas are strictly off-limits because sudden hazardous steam-driven explosions may occur and high concentrations of toxic gases may accumulate.

Solidum said the entire Volcano Island is a permanent danger zone, and permanent settlement in the island is strictly not recommended.

He added that breathing air with high concentration of gases can also be lethal to human and animals and can even cause damage to vegetation.

Explaining the basis of the alert upgrade, Phivolcs said at least 21 volcanic quakes were detected by the seismic network, ranging from intensities two to three, in the past 24 hours. One of them was accompanied by rumbling sounds.

The agency likewise monitored a build-up of carbon dioxide emissions at the Taal Main Crater Lake, which nearly tripled at 4,670 tons per day in the last week of March 2011 from only 1,875 tons per day in February.

The remarkable increase in carbon dioxide concentration indicates its release from the magma at depth, Solidum said.

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

Taal, one of the world's lowest volcanoes at only 311 meters above sea level, had its last eruption in October 1977. It erupted 33 times since monitoring began in 1572.

Despite the hazards posed by Taal, the Volcano Island has been attracting settlers because of its fertile soil and rich fishing grounds. Taal Lake is known for several varieties of milkfish, carps, maliputo, and tawilis.

While Taal's activity intensified Saturday, two of the country's 22 most active volcanoes did not exhibit abnormal activities so far.

Phivolcs said the Mayon volcano in Albay and nearby Bulusan volcano in Sorsogon are still under Alert Level 1.

Although this means that no eruption is imminent, it is recommended that the public should not enter the six-kilometer radius permanent danger zone due to the continuing threat from sudden small explosions and rock falls from the upper and middle slopes of Mayon volcano.

Active stream or 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.

For Bulusan, Phivolcs advised the public not to enter the four-kilometer radius permanent danger zone 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.

Around 2,000 people were evacuated in several towns in Sorsogon after an ash explosion last February 21. They were asked to return to their homes days later after Bulusan showed no signs of further unrest.

Bulusan, located just 70 kilometers southeast of Mayon, is the fourth most active volcano in the Philippines after Mayon, Taal, and Pinatubo in Zambales. (Sunnex)