LEGAZPI CITY, Philippines – The Philippine Institute of Volcanology and Seismology (Phivolcs) has deployed more personnel to monitor Bulusan Volcano, which erupted four times last week.
Ed Laguerta, Phivolcs scientist, said yesterday a six-man geodetic team was deployed to the Bulusan observatory in Barangay Cabid-an in Sorsogon City.
Phivolcs said the volcano remains under alert level 1 as there could be more phreatic or steam-driven eruptions.
Laguerta said the phreatic explosion on Oct. 22 that reached 2.5 kilometers high was strong.
He said close monitoring is needed to detect changes in sulfur gas output as well as inflation and magma content of the ashfall to determine if there is a need to raise the alert level.
“The earthquakes that have been observed and the geochemistry of the ash showed no indication of a magmatic eruption,” said Laguerta.
“If the phase of eruption changes from phreatic to magmatic, our present alert level will change,” he said.
Laguerta said around 200 residents of Sitios Talistison and Amoquid in Barangay Mapaso in Irosin town had been evacuated. He said villagers are at risk from super-heated gas, which accompany ash-driven explosions.