Expansion Of Danger Zone Around Bulusan Advised

By Bobby Labalan
Inquirer, Agence France-Presse
Posted 06:14pm (Mla time) June 19, 2006

SORSOGON CITY -- The Philippine Institute of Volcanology and Seismology (Phivolcs) has advised local officials to expand to five kilometers the radius of the Permanent Danger Zone to ensure the safety of those living around Bulusan volcano.

Frequent ash emissions from the volcano could pose a threat to surrounding areas although there is little danger of a major eruption, Phivolcs chief Renato Solidum said Monday.
But he warned that hazards remain due to the large volume of volcanic debris spread over the summit and surrounding hillsides.

"As the rainy season progresses, this accumulated loose volcanic material whether old or new shall be eroded, mobilized and mixed with rainwaters which could form in hazardous lahars and torrential flows," he said.

Dr. Ernesto Corpuz, chief of the Volcano Monitoring and Eruption Prediction Division, said that with the onset of the rainy season residents face two grave dangers--from ashfall and lahar flow.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration announced that more rains brought by the southwest monsoon are expected in the next few days here in Sorsogon.

The 5,134-foot Bulusan mountain in the central region of Bicol began a period of minor activity in late March.

But the lack of volcanic quakes accompanying the ash explosions and the low levels of sulfur dioxide being emitted "suggest that no large or active magmatic intrusion into shallow depths has taken place," said Solidum.

Instead, the activity points to an "interaction of small volumes of magma with an overlying water-saturated zone beneath the summit," he said.

"It remains to be seen if the recent explosions would provide an uncorking effect and induce a major hazardous eruption, because the very low earthquake activity suggests otherwise," he added.

The advice to expand the danger zone was issued as evacuation was ongoing in the two most affected towns of Juban and Casiguran Monday morning.

"Though no eruption is imminent at this moment, ash explosions are expected--which may endanger the women, children and the elderly, especially those who are sick," he said.

Under the Bulusan advisories, alert level 2 may cover up to five-kilometer radius of the PDZ from four kilometer radius, he added.

"It's a judgment call on the part of the local officials since they are more familiar with the terrain in their respective jurisdictions," the Phivolcs official pointed out.

As of press time, 319 persons comprising 56 families were already housed at the Jose Alindogan Elementary School in the village of Tugah, Juban and 60 families composed of 341 persons were already evacuated to the Casiguran Vocational High School.