Increased seismicity observed in Kanlaon Volcano

2024 July 4

MANILA – An increase in the number of volcanic earthquakes has been observed in Kanlaon Volcano, totaling 90 from 3 p.m. Tuesday to 12 noon Wednesday, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

Most of these quakes were 20-km. deep. Five volcano-tectonic earthquakes produced by rock fracturing, and 85 weak-low frequency earthquakes that indicate the movement of volcanic fluids were also stated in the Phivolcs advisory.

“There is an average of 10 earthquakes per day since the volcano’s June 3 eruption. The increase in (seismicity) is likely due to the magma moving beneath the volcano. This movement also causes more gas to be released and the ground to swell,” Phivolcs Director Teresito Bacolcol said in an interview.

Phivolcs on Tuesday reported an average of 5,083 tons of sulfur dioxide (SO2) emission in Kanlaon Volcano, lower than an average of 5,397 tons of SO2 recorded on June 28.

Kanlaon has been degassing increased concentrations of volcanic SO2 this year at an average rate of 1,273 tons per day before the June 3 eruption. However, emission since then has been particularly elevated at a current average of 3,254 tons per day.

“The overall monitoring parameters indicate that magmatic processes beneath (the) volcano may be driving current unrest, causing increased volcanic earthquake activity, persistently high concentrations of volcanic gas emission and swelling of the edifice,” the advisory read.

Bacolcol said Kanlaon’s Alert Level 2 status would be maintained for now.

At Alert Level 2, the current unrest driven by shallow magmatic processes could lead to explosive eruptions or precede hazardous magmatic eruptions at the summit crater.

“We will assess this on a day-to-day basis and observe it over the next few days. If the increase in earthquakes and SO2 emission persists, then we will raise the alert level,” Bacolcol said.

He cited as an example the Taal Volcano eruption in 2020 when Phivolcs had to raise the alert level status from 1, 2, 3, and 4 within a day.

Meanwhile, the public is strongly advised to refrain from entering the 4-km. permanent danger zone to minimize risks from volcanic hazards, such as pyroclastic density currents, ballistic projectiles, and rockfall.

Aviation authorities are urged to advise pilots to avoid flying close to the volcano’s summit as ash and ballistic fragments from sudden eruptions can be hazardous to aircraft. 

Canlaon City marks Charter Day with ‘caution’

Meanwhile, Mayor Jose Chubasco Cardenas of Canlaon City, Negros Oriental led residents in celebrating its 57th charter day with vows of continued resilience and commitment to overcome adversities.

Doing away with the usual fanfare and festivities, the city celebrated on Tuesday with simple activities in solidarity with the disaster challenges that the residents are still facing.

The celebration was “tempered by caution” but also reflected a “city poised to overcome challenges and continue its journey towards a prosperous future”, the city’s Salta Canlaon Official Facebook page said.

“Thank you for your unwavering support and dedication. Your efforts have been instrumental in our city’s growth,” Cardenas said.

“It is important to stay vigilant and prepared,” he added.

Ma. Cristina Arayata (PNA)