The ground rumbled and Kanlaon Volcano suddenly spewed a gray voluminous plume above its crater causing the sky to turn dark at 5:51 a.m. Tuesday, April 8.
Pockets of what looked like small fires were also seen on the side of the volcano, La Castellana Mayor Rhummyla Nicor Mangilimutan said.
Mangilimutan witnessed the eruption Tuesday morning from the second floor of a building in Barangay Cabacungan, La Castellana.
The mayor said it was a scary site as the wind blew the ash mostly in the direction of La Carlota City, which was the worst hit.
La Castellana residents within the 6 kilometer danger zone luckily remain in evacuation centers away from harm, she said.
What appeared to be small fires on the side of the volcano were hot ballistic fragments spewed by the volcano, Irene Bel Ploteña, Provincial Disaster and Risk Reduction Management Office head, said.
It was a moderate eruption and Kanlaon remains under Alert Level 3, she said.
Sugar industry leader Manuel Lamata said he had just taken off from the Bacolod Silay Airport on board his private plane when he suddenly saw the sky turn dark above Kanlaon.
“It was very scary”, he said.
Kagawad Bernie Rojo of Barangay San Miguel, La Carlota City, said when he went out of his house Tuesday morning thick grey ash was rising into the sky before it fell to the ground beyond the six-kilometer danger zone that had already been cleared of residents.
The Philippine Institute of Volcanology and Seismology said a moderately explosive eruption occurred at the summit crater of Kanlaon Volcano at 5:51 a.m. Tuesday that lasted 56 minutes based on seismic and visual recordings.
The eruption on Tuesday was less intense than the eruption of Dec. 9 but lasted longer, Mari-Andylene Quintia, resident volcanologist of the Phivolcs based in La Carlota City
She said a 75-meter ash emission from the crater drifting southwest also occurred from 1:11 to 1:32 p.m. on Tuesday.
The earlier eruption at 5:51 a.m. generated a gray voluminous plume that slowly rose to 4,000 meters above the vent before bending and drifting west and southwest, Phivolcs said.
Audible rumbling sounds of the eruption were reported in Brgys. Biak-na-Bato and Sag-ang, La Castellana, Negros Occidental,and Brgy. Pula in Canlaon City, Negros Oriental.
Pyroclastic density currents (PDCs) descended the southern slopes within a kilometer of the crater, in the jurisdiction of La Castellana, based on visual and thermal camera monitoring.
Large ballistic fragments were also observed to have been thrown around the crater within a few hundred meters and caused burning of vegetation near the volcano summit.
Heavy to light ashfall hit La Carlota City, La Castellana, Hinigaran, Pontevedra, San Enrique and Bago City in Negros Occidental, the PDRRMO reported.
The hardest hit was La Carlota, and sulfuric smell was prevalent, it said.
Classes were suspended in La Carlota City, La Castellana, Pontevedra, Bago City and Isabela.
Mayor Rex Jalandoon said he also suspended work in government offices in La Carlota.
Sulfur and ash blocked water supply affecting about 3,000 residents in barangays Araal and San Miguel in La Carlota, Jalandoon also said.
The La Carlota and Negros Occidental provincial governments sent waters tanker to provide residents with water.
Houses, vehicles, plants and roads were covered in ash in some parts of La Carlota City.
Local government units and the provincial government distributed face masks.
No additional evacuation was ordered since Kanlaon remains under Alert Level 3, Donato Sermeno III, OCD Negros Island Region head, said.
The eruption was preceded by short-term inflation or swelling of the southeastern side of volcano that began on Jan. 10, along with a decline in average sulfur dioxide (SO2) emission from 4,014 tons to 1,655 tons on Tuesday.
There was no significant change in the average occurrence of volcanic earthquakes of 14 a day since June 3.
These parameters indicate that the blockage of volcanic gas emission resulted in the pressurization and swelling of the edifice triggering a moderately explosive eruption at Kanlaon, Phivolcs said.
No pronounced increases in volcanic earthquakes, ground deformation or volcanic gas parameters have followed the eruption on Tuesday, Phivolcs said.
Tuesday’s eruption may be followed by similar short-lived explosive eruptions in the short term or even progress to lava eruptions that generate lava flows and lava fountaining activity, Phivolcs said.
Phivolcs has recommended that residents from the 6-km radius of the summit crater remain evacuated due to the danger of potential pyroclastic density currents, ballistic projectiles, rockfalls, ashfall and other related hazards that could be posed by similar explosive eruptions.
Increased vigilance must be exercised should intense rains occur since loose ash or pyroclastic material have been deposited in the upper slopes and could easily be eroded to generate lahars and sediment-laden streamflows in channels draining the southern and western portions of the edifice, Phivolcs said
Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft, it added.*