Concern in Colombia due to increased activity of the Nevado del Ruiz volcano

The Nevado del Ruiz is a stratovolcano that is part of the Andes mountain rangelocated 220 km west of Bogotá (Colombia).

The first eruptions occurred 1.8 million years ago, at the beginning of the Pleistocene; today the smoke coming out of the eternal snow crater reminds the surrounding villagers –not forgetting the devastating 1985 eruption-, the constant threat that this colossus represents.

Nevado del Ruiz had its most recent eruption at 9:09 PM on November 13, 1985. Within hours, an entire city was razed to the ground by the ensuing avalanche and 25,000 people were covered in mud in the worst natural disaster in the country’s history.

Subsequently, the dacitic tephra ejected more than 30 km into the atmosphere. The eruption reached level 3 on the Volcanic Explosivity Index. The lahars, made up of water, ice, incandescent pyroclastic material, pumice, sand, mud and other rocks, mixed as they descended the slope.

Luis Londoño still remembers that “very scared” November 13. At night, a nearby river “roared” and people everywhere were “crying and screaming that this was the end of the world,” he told the agency. AFP.

A resident of Herveo, a municipality near the volcano, fears the tragedy will repeat itself.

“The fear is great that the snow will explode, is the comment of the entire municipality”, says the 65-year-old man who has not yet decided to evacuate.

El Ruiz went around the world with the image of Omaira Sánchez, a 13-year-old girl who died after the avalanche that covered the city of Armero He was stuck with mud up to his neck and legs in the rubble of his house.

Orange alert

Nicknamed the sleeping lion, El Ruiz went through decades of lethargy prior to the 1985 avalanche and erupted again a decade ago. The threat has been felt since the end of March, when the daily average of earthquakes in the volcano went from 50 to 12,000.

Then the authorities increased yellow to orange blowout risk warning and they ordered the evacuation of the areas around the Ruiz, where some 57,000 people are at risk.

“The farmers have cows, horses, cattle, goats and poultry, and that somehow prevents them from moving around and carrying out the preventive evacuation (…) for fear of being robbed”, acknowledged the presidential adviser Luis Fernando Velasco.

But before the refusal of the majority of the local population to comply with the order, the national government “exceptional measures to move about 80,000 animals (…) from alert areas”said a bulletin.

Few travel the steep trails that surround the volcano. Some farmer passes by with his mule and his face is red from the cold of about 3° C. Some soldiers check the way to the nature tourist park that is closed today.

President Gustavo Petro called for the evacuation of some 7,500 people living in the areas closest to Ruiz to be expedited.

The Colombian Geological Survey (SGC) issues daily bulletins on the volcano’s activity, and while data fluctuates, the warning is maintained.

In one of the most recent he indicated that the seismic activity associated with rock breaking in the volcanic edifice is still in the southwest sector of the volcanoat a depth between 2 and 4 km and at a distance from the crater between 2 and 6 km.

On Tuesday, April 11, the maximum magnitude was 1.3, corresponding to the 05:03 earthquake, located 4 km SW of the crater and about 3 km deep from the top of the volcano.

The SGC indicated that while the volcano’s activity may fluctuate in orange levels and sometimes decrease compared to previous days, this does not mean that you have returned to a lower activity level.

To change the level and return to the yellow level, a cautious time is needed where trends and patterns can be observed that allow us to deduce the possible decrease in activity, therefore it is warned that the activity level of the Nevado del Ruiz volcano will remain orange for several weeks.

During this time, in the event of an acceleration of processes suggesting an imminent eruption or the eruption itself occurring, the activity level changes to red, the SGC indicates.

“We are concerned that the earthquakes are moving closer to the crater and that, according to volcanologists, is not the best sign,” advised Velasco.