MANILA — Volcanic activity in Mount Kanlaon in Negros may be pointing towards higher chances of a phreatic eruption, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Friday.
The volcano has been under Alert Level 1 since 2020 due to an increase in low-frequency volcanic earthquakes.
Based on its latest monitoring, Phivolcs has observed at least 3 volcanic earthquakes, with the volcano's edifice inflated. On Monday, Kanlaon also emitted over 1,000 tons of sulfur dioxide.
Phivolcs Chief Science Research Specialist Maria Antonia Bornas said that while magmatic eruptions are still more dangerous compared to phreatic eruptions, the latter can still be worrisome.
"Ang problema sa phreatic eruption, maraming ganitong klaseng pagputok ang nagaganap ng walang precursory signals. Sa mga nakalipas na taon, pawang mas maraming pinapatay ang phreatic eruption kesa sa magmatic eruption," Bornas said.
(The problem with phreatic eruptions is that many such eruptions occur without precursory signals. In recent years, phreatic eruptions have killed more than magmatic eruptions.)
Bornas added that during Kanlaon’s phreatic eruption in 1996, 3 people were killed after being hit by volcanic debris.
Aside from phreatic eruption, state volcanologists are also not ruling out the possibility of other volcanic hazards.
“Matagal nang hindi nagkakaroon ng totoong magmatic eruption ang Kanlaon Volcano. Batay sa kaniyang geology, ito ay maaaring maglabas ng napakaraming lava flow. Pangalawa, pwede itong sumabog explosively. Pangatlo, pwede itong magkaroon ng flank eruption, 'yung sa tagiliran, hindi natin ma-eexpect 'yun mga ganiyan," the Phivolcs official said.
(Kanlaon Volcano has not had a true magmatic eruption for a long time. Based on its geology, it can release a lot of lava flow. Second, it can explode explosively. Third, it can have a flank eruption, the one on the side, we can't expect that kind of thing.)
Kanlaon also has a history of a debris avalanche, which makes an eruption dangerous. Unlike the Mayon and Taal volcanoes, a plume has not been observed over Kanlaon.
Nevertheless, state volcanologists advised against entry into Kanlaon's 4-kilometer radius permanent danger zone, as well as flying aircraft close to the volcano.