MANILA, Philippines — State volcanologists raised the alert level on Kanlaon Volcano in Negros Oriental yesterday due to increased seismic activity in the past several days.
“Alert Level 1 prevails over Kanlaon Volcano, which means that it... has entered a period of unrest,” the Philippine Institute of Volcanology and Seismology (Phivolcs) said in its bulletin.
Phivolcs advised the public not to enter the four-kilometer radius permanent danger zone due to possibilities of sudden and hazardous steam-driven or phreatic eruptions.
Kanlaon Volcano’s seismic monitoring network recorded 80 volcanic earthquakes, of which 77 were classified as low-frequency events associated with magmatic fluids beneath the edifice.
“The increased seismic activity could be succeeded by steam-driven or phreatic eruptions at the summit crater despite the absence of visible degassing or steaming from the active vent,” Phivolcs said.
The agency said ground deformation data since 2017 has indicated a period of long-term slow inflation of the edifice. Short-term electronic tilt monitoring on the southeastern flanks have recorded slow inflation of the lower slopes since May 2019 and pronounced inflation of the upper slopes in the latter part of January.
“These parameters indicate that volcanic processes are underway deep beneath the edifice that may be caused by deep-seated degassing or hydrothermal activity or magmatic intrusion,” it said.
Kanlaon is one of the active volcanoes in the country.