Mt. Kanlaon 

MANILA – Kanlaon Volcano in Negros Island is showing signs of increased activity, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported Friday.

In an advisory, Phivolcs said 18 volcanic earthquakes were recorded within the last 24 hours. The number includes four "very shallow tornillo signals" associated with magmatic gas along fractures within the upper volcanic slopes.

Phivolcs also noticed slight deformation of the edifice since mid-October last year.

"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 crater," it added.

Volcanic quakes are caused by movements or eruptions of magma from the volcano. On the other hand, shallow tornillo signals are a low frequency earthquake that are tornillo or screw in shape.

Weak to moderate and low steam-laden plumes reaching 200 meters high was observed last January 16.

Alert Level 1 (abnormal) is maintained over the Kanlaon Volcano.

Entry into the 4-kilometer radius permanent danger zone must be strictly prohibited, Phivolcs said due to possibilities of sudden steam-driven or phreatic eruptions.

Pilots are also advised to avoid getting near the volcano's summit as phreatic eruption can be hazardous to aircraft. (PNA)