Bulusan, Kanlaon being watched following quakes
Amid successive quakes in different parts of the country, the Philippine Institute of Volcanology and Seismology (Phivolcs) is also monitoring the restiveness of both Kanlaon and Bulusan volcanoes, as it warned of possible steam-driven or phreatic eruptions in Bulusan.
In an advisory on Sunday, Phivolcs noted an “increase in seismic activity” at the volcano in Sorsogon province.
A total of 72 volcanic earthquakes were recorded by the since 12 a.m. of Saturday, the agency said.
“These volcano-tectonic (VT) earthquakes are associated with rock fracturing and are occurring at depths less than 10 kilometers beneath the northern sector of the volcano,” the bulletin said.
While “degassing activity from the active vents ranged from very weak to weak when the volcano was visible for the past days,” the advisory noted that “sulfur dioxide or SO2 emission was recorded at an average of 31 tonnes/day, measured on 09 October 2025.”
“Alert level 1 (low-level unrest) is maintained over Bulusan Volcano, [even as] there are increased chances of steam-driven or phreatic eruptions occurring from the crater and/or its active vents on the summit that could occur suddenly and without warning.”
The agency warned of “possible impacts of volcanic hazards such as pyroclastic density currents or PDCs, ballistic projectiles, rockfall, avalanches, ashfall and others on these danger areas.”
“Furthermore, people living within valleys and along river/stream channels especially on the western sectors…should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur.”
Still restive
Phivolcs also reported a 30-minute ash emission at Kanlaon rising up to 300 meters on Sunday morning.
Over a 24-hour period on Saturday, three volcanic quakes were also logged, the agency said, adding that a total of 2,968 tons of sulfur dioxide were released, more than the 1,238 tons released on Friday.
Kanlaon also emitted a plume that rose 1,000 meters tall which drifted east-northeast.
The volcano remains under alert level 2 or increased unrest.
