Kanlaon Volcano in Negros province had 41 volcanic earthquakes since June 30, the Philippine Institute of Volcanology and Seismology said on Sunday.
Phivolcs placed Kanlaon under alert level 1 (low level unrest).
The Kanlaon Volcano Network said the tremors included seven very shallow tornillo signals associated with volcanic gas movement along fractures within the upper volcanic slopes.
Based on the ground deformation data, the volcano edifice has slightly deflated.
“These are consistent with continuous electronic tilt recording of inflation of southeastern flanks since mid of March 2022,” Phivolcs said.
Entry into the four-kilometer radius permanent danger zone of Kanlaon is not allowed, as well as flying of any aircraft close to the volcano.
Possible hazards that can occur are sudden steam-driven or phreatic eruptions.
Phivolcs noted that ground deformation data from continuous GPS measurements indicated short-term slight inflation of the lower and mid slopes since January 2022. Rio N. Araja
“The increased seismic activity and short-term ground deformation are likely caused by the shallow hydrothermal processes beneath the edifice that could generate phreatic or steam-driven eruptions from the summit crater,” it added.