Kanlaon Volcano has showed a notable increase in volcanic tremors, with six prolonged episodes lasting over an hour.
The Philippine Institute of Volcanology and Seismology (Phivolcs) reported on Sunday, December 29, that it recorded 16 volcanic earthquakes, including six volcanic tremors lasting from 49 up to 84 minutes, within the past 24 hours.
Phivolcs observed two ash emissions from the volcano, with each lasting up to 49 minutes. The plumes rose to 1,200 meters and drifted westward.
The agency recorded sulfur dioxide emissions at 3,984 tons per day and detected continued swelling of the volcano through ground deformation studies.
Phivolcs urged the public to evacuate within a 6-kilometer radius of the volcano’s crater. It also advised residents on the western side to prepare for potential ashfall after ash emissions occurred early Sunday morning.
The agency warned pilots to avoid flying near the summit because of the potential hazards from ash plumes.
Kanlaon Volcano remains under Alert Level 3, indicating high levels of volcanic unrest and the possibility of a hazardous eruption.
Kanlaon alert scheme
Here is the alert scheme for Kanlaon Volcano, which Phivolcs has set, including the key parameters:
- Level 0: No Alert (Normal)
Criteria: All monitored parameters within background levels. Unremarkable level of volcanic earthquakes occurring within the volcano area.
Interpretation/Recommendation: The volcano is in a state of quiescence, and no magmatic eruption is foreseen. However, perennial hazards such as sudden explosions, rockfalls, and landslides may occur suddenly and without warning within the four (4)-kilometer-radius Permanent Danger Zone (PDZ).
- Level 1: Low Level of Volcanic Unrest
Criteria: Slight increase in volcanic earthquakes and steam/gas activity. Sporadic explosions from the summit crater or new vents. Notable increase in the temperature, acidity, and volcanic gas concentrations of monitored springs and fumaroles. Slight inflation or swelling of the edifice.
Interpretation/Recommendation: Hydrothermal, magmatic, or tectonic disturbances may be underway. The source of activity may be shallow, near the summit crater, or in the vicinity of the edifice. Entry into the PDZ must be prohibited.
- Level 2: Moderate Level of Volcanic Unrest
Criteria: Elevated levels of volcanic earthquakes, temperature, acidity, and volcanic gas concentrations of monitored springs and fumaroles, steam and ash explosions from the summit crater or new vents, inflation or swelling of the edifice.
Interpretation/Recommendation: Probable intrusion of magma at depth, which may or may not lead to a magmatic eruption. Entry within PDZ must be prohibited.
Much risky
- Level 3: High Level of Volcanic Unrest
Criteria: Sustained increases in volcanic earthquakes, some of which may be perceptible. More energetic and frequent steam/ash explosions. Sustained increases in the temperature, acidity, and volcanic gas concentrations of springs and fumaroles, and in the levels of ground deformation or swelling of the edifice. Activity at the summit may involve sluggish lava extrusion with resultant rockfall.
Interpretation/Recommendation: Magmatic intrusion to shallow levels of the edifice is driving unrest, with indications that hazardous eruption could occur in weeks. Danger zones may be expanded to a radius of six (6) kilometers from the summit crater or active vent.
- Level 4: Hazardous Eruption Imminent
Criteria: Intensifying unrest characterized by earthquake swarms and volcanic tremor, many of which may be perceptible. Frequent strong ash explosions. Increasing rates of ground deformation and swelling of the edifice. Increasing rates of lava extrusion with increased frequency and volume of rockfall and volcanic gas flux, or abrupt decrease in volcanic gas flux due to plugging of lava at the summit crater or active vent.
Interpretation/Recommendation: Low-level magmatic eruption underway, which can progress to a highly hazardous major eruption within hours or days. Danger zones may be expanded to a radius of ten (10) kilometers or more from the summit crater or active vent.
- Level 5: Hazardous Eruption in Progress
Criteria: Magmatic eruption characterized by explosive production of tall ash-laden eruption columns, and/or descent and frequent failure of voluminous lava flows. Generation of deadly pyroclastic flows, surges, and/or lateral blasts and widespread tephra fall (ashfall). Lahars generate along river channels.
Interpretation/Recommendation: Life-threatening major eruption producing volcanic hazards that endanger communities. Danger zones may be expanded to fourteen (14) kilometers as eruption progresses.
Reymund Titong is a Filipino journalist steadily building his voice in the field of news reporting, driven by a commitment to tell meaningful and relevant stories.
He serves as a correspondent for Rappler, maintains a personal blog on Medium, and is the communications officer of Hope Builders Organization Negros Island.