Seismic activities of Bulusan, Kanlaon volcanoes increased 鈥� Phivolcs
STILL RESTIVE Mt. Kanlaon on Negros Island, shown here from the town of La Castellana in Negros Occidental, spews ash for two hours on Monday starting at 11:52 a.m. but only caused minor ashfall in nearby areas. The volcano erupted on April 8. —MARVIN ESCANDER/CONTRIBUTOR
MANILA, Philippines — State seismologists observed an increase in the seismic activities of Bulusan and Kanlaon volcanoes on May 12.
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In an advisory issued Monday afternoon, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported detecting 309 volcanic earthquakes at Bulusan Volcano since midnight of May 8.
Of these, 287 were volcano-tectonic (VT) earthquakes linked to rock fracturing at shallow depths of less than 4 kilometers beneath the southeastern edifice of Bulusan Volcano, while 22 were low-frequency volcanic earthquakes (LFVQs) associated with fluid movement.
State seismologists said degassing activity from the active vents has been weak to moderate when the volcano has been visible for the past days.
“These changes in parameters may indicate shallow hydrothermal activity of the Bulusan Volcano,” Phivolcs said.
Alert level 1, or “low level unrest,” is maintained over Bulusan Volcano, which means there are increased chances of phreatic eruptions.
“Local government units and the public are reminded that entry into the 4-kilometer radius Permanent Danger Zone must be strictly prohibited and that vigilance in the 2-kilometer Extended Danger Zone on the southeast sector must be exercised due to the possible impacts of volcanic hazards such as pyroclastic density currents or PDCs, ballistic projectiles, rockfall, avalanches, ashfall and others on these danger areas,” Phivolcs said.
“Communities that experience ash fall must take all necessary precautions and use protective masks or wet cloths to prevent ash inhalation, with special attention given to vulnerable persons, including the elderly, persons with respiratory or cardiovascular diseases, expecting mothers and infants,” it added.
In another advisory issued on Monday, Phivolcs said it recorded 72 volcanic earthquakes at Kanlaon Volcano between 12:00 a.m. and 12:00 p.m. on May 12.
“Volcanic sulfur dioxide (SO2) gas emissions from the summit crater of Kanlaon based on measurements yesterday, averaged 554 tons per day. There has been a decline in the average sulfur dioxide emission from 4,144 since June 3, 2024 to 2,114 since April 1, 2025,” it added.
Alert Level 3 or magmatic unrest prevails over Kanlaon, which means that the volcano is in a state of magmatic unrest, and currently there are increased chances of short-lived moderately explosive eruptions occurring that could generate life-threatening volcanic hazards.
