Kanlaon Volcano, which has been hit with volcanic-tectonic (VT) earthquake swarms for four consecutive days, spewed ash for more than an hour Wednesday morning, Sept. 17.
The first ash emission, described as weak, began at 6:18 a.m. and ended at 7:27 a.m. on Wednesday, said Ptolemy Mañego, a Science Research Assistant at the Philippine Institute of Volcanology and Seismology (Phivolcs) Kanlaon Volcano Observatory in La Carlota City.
Another weak ash emission also occurred at 7:54 p.m. Wednesday and lasted for about two minutes, he said.
There was no reported ashfall in nearby communities, he said.
“This is an indication that Kanlaon is in an active state based on its latest seismic activity,” Mañego said.
There were 60 VT earthquakes in the past 24 hours at Kanlaon, Phivolcs reported on Wednesday.
Phivolcs reported 176 VT earthquakes on Tuesday, 72 on Monday, and 41 on Sunday.
VTs are generated by rock fracturing processes. The increase in VT activity strongly indicates progressive rock fracturing beneath the volcano as rising magma or magmatic gas drives a path toward the surface, Phivolcs said.
Kanlaon also spewed 1,500 tons of sulfur, Phivolcs reported on Wednesday.
Phivolcs said the public is reminded that Alert Level 2 prevails over Kanlaon, which means that the volcano is in a state of increased unrest.
“The increase in VT events could lead to increased chances of steam-driven or phreatic eruptions or short-lived weak to moderately explosive eruptions occurring at the summit,” Phivolcs said.
“These could generate life-threatening volcanic hazards such as pyroclastic density currents or PDCs, ballistic projectiles, ashfall, rockfall and other,” it said.
Phivolcs has strongly recommended that communities within the 4-km Permanent Danger Zone of Kanlaon strictly remain evacuated and that those within the 6-km radius from the summit crater be vigilant and ready in case unrest worsens.
Kanlaon has the highest peak in the Visayas, with an elevation of 2,465 m (8,087 ft) above sea level.
The volcano straddles the provinces of Negros Occidental and Negros Oriental.*