BY DOMINIQUE GABRIEL G. BAÑAGA
BACOLOD City – The Philippine Institute of Volcanology and Seismology (Phivolcs) noticed increased activity in Mt. Kanlaon volcano.
Its network of seismometers in Negros Island recorded 18 volcanic earthquakes in the last 24 hours, Phivolcs’ Jan. 21 bulletin stated.
Kanlaon volcano straddles the border shared by Negros Oriental and Negros Occidental. At 2,465 meters above sea level, it is the highest point in Negros Island and in the Visayas.
According to Phivolcs, four of the tremors were described as very shallow tornillo signals associated with magmatic gas movement along fractures within the upper volcanic slopes.
Volcanologists also noted a degassing activity from the volcano’s crater. Very weak to moderate and low steam-laden plumes rose up to 200 meters before drifting northwest.
Degassing was last observed in the volcano on Jan. 16.
Kanlaon, part of the Negros Volcanic Belt, is a large stratovolcano dotted with numerous flank cones and craters, many of which contain lakes. The volcano is the most active in Central Visayas.
Ground deformation data from Phivolcs’ GPS measurements indicated short-term slight inflation of Kanlaon’s edifice observed since mid-October 2021.
Phivolcs added the increased activity is likely caused by shallow hydrothermal processes beneath the volcano’s edifice, and they warned it could generate phreatic or steam-driven eruptions.
Kanlaon’s last phreatic eruption was on Dec. 20, 2017.
In March of 2020, Kanlaon also exhibited increased unrest. There was a series of strong earthquakes, with the strongest at magnitude 4.7 on June 21, 2020.
Kanlaon has been placed on Alert Level 1 since 2020./PN
