LEGAZPI CITY: Philippine Institute of Volcanology and Seismology (Phivolcs) Director Renato Solidum warned disaster officials and the public to be on guard as Mount Bulusan will be exhibiting a series of steam-driven explosions due to ongoing hydrothermal processes beneath the restive volcano.
He said most of the ejected ashes of Mouth Bulusan since May 1 to June are old deposits.
“(There is) no fresh or juvenile magma build up detected so there is no possibility of explosive magmatic-related eruption. But steam-driven explosions will continue,” Solidum said.
The continuing abnormality of the volcano in Sorsogon province is already affecting the source of potable water of nearby communities.
A report from the provincial disaster risk reduction management office (PDRRMC), headed by Ruben Dimaano, states that at least 35,000 people are affected as ash has fallen on vital sources of potable water.
The five villages hit by ash fall were barangays Anog, Puting Sapa, Katanusan, Bacolod and Bura-buran with a total population of 5,713 persons.
Phivolcs geologists are conducting a thorough study in the past few weeks to look into the chemical composition if there are changes that might lead to magmatic eruption.
But based on the study according to Solidum there are no changes in the chemical composition detected.
Phivolcs officials in Bicol requested the Office of Civil Defense Bicol and Tactical Operations Group 5-Philippine Air Force for another round of an aerial survey to conduct thorough study over the restive volcano but choppers are not available as of press time.
Alert Level 1 remains in effect over Bulusan Volcano and this indicates that hydrothermal processes are underway beneath the volcano that may lead to more steam-driven eruptions.
Phivolcs and the Office of Civil Defense in Bicol reiterated to local government units and the public not to entry to the 4-kilometer radius Permanent Danger Zone (PDZ) due to the possibility of sudden and hazardous steam-driven or phreatic eruptions.
Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft.
People living within valleys and along river and stream channels especially on the southwest and northwest sector of the edifice is strictly advised to be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall.