MANILA, Philippines - The Philippine Institute of Volcanology and Seismology (Phivolcs) recorded over 250 volcanic earthquakes at Mt. Kanlaon in Negros Occidental in less than two weeks and government volcanologists allayed fears of an impending major eruption.
Jaime Sincioco, officer-in-charge of the Phivolcs’ Volcano Monitoring and Eruption Prediction Division, said 257 volcanic earthquakes were detected by the seismic network from Aug. 23 to Sept. 1.
Sincioco said the seismic activity is notably higher than the usual levels, which generally varies from zero to four quakes detected in 24 hours during quiet periods.
Phivolcs said two of these quakes occurred at 5:26 p.m. on Aug. 23 and was felt at Intensity 2 in Barangay Ara-al, La Carlota City and at 10:27 p.m. on Aug. 30, felt at Intensity 3 in La Castellana and Intensity 4 in La Carlotta City and Bago City.
Phivolcs said the epicenters of the recorded quakes clustered at the northwest slope of the volcano.
“The occurrences of these earthquakes may indicate movements of an active local fault at the slope of the volcano which may be induced by pressure beneath the volcano,” Phivolcs said in an advisory.
Sincioco said Phivolcs maintained Alert Level O over Kanlaon but he warned the public against entering the four-kilometer permanent danger zone due to sudden ash explosion.
He said they still have to monitor other parameters, such as steaming activity of the volcano, before increasing the alert level of Kanlaon.
Sincioco said surface observations, however, did not indicate significant change in the steam emission from the crater.
“If the prevailing elevated level of seismic activity continues together with other monitored parameters, the alert level status of the volcano will be raised accordingly,” the agency said.
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Phivolcs director Renato Solidum said the increase in seismicity is likely related to a local fault or faults at Kanlaon slopes, movement of which may be related to pressure below.
“There are no additional data to indicate if this will lead to increased volcanic activity,” he said.
Phivolcs said “since Kanlaon volcano has a history of sudden steam-driven explosions without precursors, the public is reminded to refrain from entering the four kilometer permanent danger zone (PDZ).”
Phivolcs also advised people planning to climb the volcano to coordinate with Phivolcs’s Kanlaon Volcano Observatory at the La Carlota City College, Cubay, Negros Occidental or its head office in Quezon City for the latest observed volcanic activity.
The 2,435-meter high volcano was listed as one of the six most active volcanoes in the country today, along with the famous Mt. Mayon in Legazpi, Albay; Mt. Pinatubo, Taal Volcano in Batangas, Mt. Bulusan in Sorsogon and Mt. Hibok-Hibok in Camiguin.