MANILA - Alert level 1 has been hoisted over three volcanoes in Luzon and one in Visayas, the Philippine Institute of Volcanology (Phivolcs) said Monday.
Placed under the alert level are Kanlaon Volcano in Negros Oriental, Bulusan Volcano in Sorsogon, Mayon Volcano in Albay and Taal Volcano in Batangas.
Phivolcs senior research specialist Rudy Lacson said steam-driven explosions prompted them to raise alert level 1 over Kanlaon Volcano on November 23, and Bulusan Volcano last May 7.
The alert was raised over Mayon Volcano last May 31, 2013.
The volcano's activity escalated in 2015, prompting Phivolcs to set alert level 3. It was later downgraded to alert level 1 last September 3.
The alert over Taal Volcano, meanwhile, has been raised since 2011 because of the hydrothermal activity in its crater.
Lacson clarified that the activities of the four volcanoes are not interrelated.
He said Phivolcs has not monitored threats of imminent eruption.
"Patuloy naman po ang monitoring natin. Kung mag-escalate po ang activity ng Kanlaon, from time to time, magbibigay naman po kami ng update," he said.
The research specialist also clarified that volcanic activity and tremors are not linked to tectonic earthquakes.
"Iba po iyung tectonic; ito po ay ang mga faultline. Sa mga volcanic earthquakes naman pong sinasabi natin, related po ito sa paggalaw ng magma... Usually po nararamdaman iyan sa local lang, sa surrounding lang ng volcano," Lacson said.