(Eagle News)–The Philippine Institute of Volcanology and Seismology on Sunday, July 3, warned about an increase in activity at Kanlaon volcano.

PHIVOLCS issued the advisory I after it monitored 41 volcanic earthquakes around the summit since 5 a.m. of June 30.

According to PHIVOLCS, these included “shallow tornillo signals that could be associated with shallow gas movement along the fractures within the upper volcanic slopes.”

Ground data also showed a “short-term slight inflation of the lower and mid slopes” since January, PHIVOLCS said.

According to PHIVOLCS, the “increased seismic activity and short-term ground deformation are likely caused by shallow hydrothermal processes beneath the edifice that could generate phreatic or steam-driven eruptions” from the summit.

PHIVOLCS said the ban on entry into the 4-kilometer radius Permanent Danger Zone should remain.

Pilots were also advised against flying near the volcano.

“(Department of Science and Technology)-PHIVOLCS is closely monitoring Kanlaon volcano’s activity and any development will be relayed to all concerned,” PHIVOLCS said.

Kanlaon remains under Alert level 1.