Kanlaon Volcano in Negros Island erupted twice in 2024, displacing close to 50,000 individuals or over 11,000 families in 32 barangays in Western Visayas and Central Visayas, according to the Office of Civil Defense 6 in a report on December 26, 2024.
Kanlaon Volcano has had episodes of phreatic or steam-driven eruptions in recent memory, being the most active volcano in the Visayas, and one of the most active in the Philippines.
However, no Negrense can ever be prepared for Kanlaon’s restiveness.
FIRST ERUPTION IN 2024
The Alert Level 1 (abnormal activity) that was hoisted over Kanlaon Volcano was raised to Alert Level 2 (increasing unrest) after an explosive eruption at the summit vent of Kanlaon Volcano at 6:51 p.m. on June 3, 2024.
According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), the eruption produced a voluminous and incandescent plume that rose rapidly to 5,000 meters above the vent.
In an advisory, PHIVOLCS stated that the eruption lasted six minutes based on the seismic record and was preceded by a relatively strong volcano-tectonic earthquake.
Coarse ashfall and sulfurous odors have been reported in communities on the western slopes of the volcano immediately after the eruption.
PHIVOLCS pointed out that Kanlaon Volcano has been exhibiting “above background earthquake activity in the early months of 2024 and degassing relatively anomalous sulfur dioxide (SO2) that has averaged approximately 1,273 tons per day."
"This means that there is current unrest driven by shallow magmatic processes that could eventually lead to further explosive eruptions or even precede hazardous magmatic eruption," PHIVOLCS began warning since June 2024.
The public has been advised strongly to be vigilant and to avoid the four-kilometer-radius Permanent Danger Zone (PDZ) to minimize risks from sudden explosions, ash fall, rockfall, and landslides.
Forced evacuation has been implemented by local government units (LGUs) thorugh their respective disaster risk reduction and management offices and councils.
In the next days, ash had fallen in Barangay Biak-na- Bato in La Castellana town located seven kilometers away from the volcano.
MUDDY FLOW
Then, the rains poured which raised the alarm of muddy streamflows and --- lahar.
PHIVOLCS reported of gray cohesive mud, plant debris, and gravel deposited by lahar along four waterways in the town of La Castellana in Negros Occidental and Canlaon City in Negros Oriental rendering Biak-na-Bato main road impassable days after the first eruption.
The lahar was reported by netizens and confirmed by PHIVOLCS' Quick Response Team (QRT) during field work, according to the Kanlaon Volcano Lahar Advisory.
The waterways affected were Tamburong Creek, which coursed through Biak-na-Bato and Calapnagan in La Castellana, Intiguiwan River in Guinpanaan and upstream Baji-Baji Falls in Cabacungan, La Castellana, Padudusan Falls in Masulog, Canlaon City; and Binalbagan River, which drains the southern flank of Kanlaon Volcano.
"The lahars were generally channel-confined but flows along Tamburong Creek overflowed and dumped a few centimeters of deposit on a stretch of the main road in Biak-na-Bato, rendering this impassable to motorists," PHIVOLCS added.
11,000 TONS OF SULFUR DIOXIDE FLUX
Kanlaon Volcano logged the highest amount of gas emission at 11,566 tons per day on September 11, 2024.
PHIVOLCS disclosed that this is the highest emission of sulfur dioxide flux from the volcano recorded since instrumental gas monitoring began after its June 3, 2024 eruption.
Earlier, PHIVOLCS noted increased seismic activity at the volcano on September 9, 2024 or just three months after it erupted.
Kanlaon, then, remained at Alert Level 2 but state seismologists warned that the series of volcanic earthquakes may lead to another eruption.
PHIVOLCS further said that sulfuric fumes were reported in the following localities: Barangay San Miguel, La Carlota City; Barangay Masulog and Barangay Pula, Canlaon City; Barangay Codcod, San Carlos City; and Barangay Inolingan, Moises Padilla.
SECOND ERUPTION IN 2024
True enough, Kanlaon Volcano’s restiveness led to another phreatic eruption on December 9, 2024, or six months after the first episode.
"An explosive eruption occurred at the summit vent of Kanlaon Volcano at 3:03 p.m. [on] 9 December 2024. The eruption produced a voluminous plume that rapidly rose to 3,000 meters above the vent and drifted west-southwest. Pyroclastic density currents or PDCs descended the slopes on the general southeastern edifice based on IP [Internet Protocol] and thermal camera monitors,” PHIVOLCS in an advisory confirmed.
PHIVOLCS said Kanlaon Volcano had six volcanic earthquakes and had a 16-minute-long ash emission event.
State seismologists noted again of an increase in the sulfur dioxide (SO2) flux emitted by Kanlaon Volcano after it released an average of 11,000 tons a day.
MUDDY STREAMFLOW
Muddy streamflow occurred anew in Barangay Biak-na- Bato, La Castellana morning on December 19, 2024.
PHIVOLCS disclosed that the ashes which mixed with stream water were relatively thin based on monitoring.
However, residents living near the stream have been warned of possible flow of a considerable amount of ashes that were deposited since Kanlaon Volcano’s phreatic eruption on December 9, 2024 should the rain persists.
“Kung mayroon pang deposits, maaaring continuous siyang ma-wash out kung may malakas na pag-ulan,” according to Engr. Mari Andylene Quintia, resident volcanologist at Kanlaon Volcano Observatory.
No plume that carries ashes was recorded on December 18, 2024, PHIVOLCS said, however, 22 volcanic earthquakes were monitored within 24 hours.
‘ALERT LEVEL 4 IS POSSIBLE’
The Office of Civil Defense (OCD) is preparing for the possible raising of Alert Level 3 (high level of volcanic unrest) to Alert Level 4 (possible explosive eruption) as experts see three potential scenarios regarding the situation of Kanlaon Volcano, according to a report of GMA News Online.
“We are preparing for a heightened alert level, and [PHIVOLCS] has advised us to maintain Alert Level 3. Preparations are underway in Himamaylan City [Negros Occidental], where we are establishing a tent city in anticipation of a possible escalation,” Regional Task Force Kanlaon Chairperson Raul Fernandez said in a statement on December 26, 2024.
Tent cities will also be built in Vallehermoso town and Guihulngan City in the Province of Negros Oriental should the need arise, the report added.
Citing PHIVOLCS, OCD 6 said that a lava flow, a violent eruption, or a plateau in volcanic activity may happen in the volcano.
Based on their assessments and comparisons with other active volcanoes, Fernandez said that the previous eruption could likely lead to a lava flow, the report further stated.
Kanlaon Volcano’s activity has already affected approximately 21,889 individuals or 7,153 families in 21 barangays of Bago City, La Carlota City, La Castellana, Moises Padilla, Murcia, Pontevedra, and San Carlos City in Negros Occidental.
The threat of the shear line, a weather system that has affected the Visayas regions in late December 2024, poses high risk of muddy streamflow and lahar that could possibly affect areas near the volcano, the report also emphasized.
In previous days, heavy rainfall affected at least 7,320 individuals or 2,305 families.
As of posting time, Alert Level 3 prevails over Kanlaon Volcano.
"Magmatic intrusion to shallow levels of the edifice is driving unrest, with indications that hazardous eruption could occur in weeks," the report reiterated.
Possible hazards from the volcano include sudden explosive eruption, lava flow or effusion, ashfall, pyroclastic density current (PDC), rockfall, and lahars during heavy rains.
The danger zone was expanded to a radius of six kilometers from the summit crater or active vent and may be expanded to 10 kilometers depending on the situation, OCD 6 underscored.
THE NUMBER OF EVACUEES
As of December 26, 2024, a total of 45,526 individuals or 11,883 families in 32 barangays in both Negros Occidental (Region 6) and Negros Oriental (Region 7) have been affected.
Of the affected population, 14,186 persons or 4,454 families were staying in 32 evacuation centers, while 6,953 individuals or 2,185 families were taking shelter outside these centers.
In addition, GMA News Online pointed out, that damage to agriculture in Western Visayas has reached P33,554,721.59 after 34.54 hectares of crops were damaged totally while 263.51 hectares were damaged partially.
A total of 830 farmers and fisherfolk have been affected.
A state of calamity was declared in the entire Province of Negros Occidental, as well as in Canlaon City and Vallehermoso town in the Province of Negros Oriental.
Moreover, OCD 6 disclosed that assistance worth P123,691,278 was provided to residents affected by Kanlaon’s activity in Western Visayas and Central Visayas.
INCREASED UNREST
As of posting time, a total of seven discrete ash emission events were recorded since December 28, 2024.
“These events generated grayish plumes that rose 100-200 meters above the crater before drifting west as recorded by the IP cameras in Barangay Mansalanao, La Castellana, and Kanlaon Volcano Observatory in Canlaon City,” according to PHIVOLCS.
The last magmatic eruption of Mount Kanlaon was recorded in 1902, according to Maria Antonia Bornas, chief of the Volcano Monitoring and Eruption Prediction Division of PHIVOLCS.
As 2024 bids farewell, Kanlaon Volcano continues to display increased unrest.
LGUs are urged to ensure continuous vigilance and preparedness while praying earnestly for the volcano to ease up before 2025.
