“I lived in this house with my wife and our three daughters. That night I was on the outskirts of the village. When I realised what was happening, I ran here. The electricity was down. People were running everywhere. We got lost. I arrived alone at the shelter. I lost my wife and two daughters.”
The eruption of the Nevado del Ruiz volcano caused a giant mudslide that flooded the village, killing around 23,000 people.
Ricardo Mendez, a volcanologist at the Colombian Institute of Geology and Mining, showed us the remains of Armero’s hospital.
“This was the main entrance to the hospital building. As you see, we are now on what was the second floor. It was just down there that emergencies came in. The first floor was completed submerged in mud,” he says.
A young volcanologist at the time, Mendez remembers visiting the scene with his colleagues to find out what had happened.
“I first came here one month after the disaster. It was total chaos. A huge marsh. People were still trying to find their loved ones. We came here to understand what had happened, the geological and hydraulic processes behind this tragedy. But what we found here was utter despair.”
25 years later, the Nevado del Ruiz Volcano is still active, although relatively quiet. Its various craters are actively monitored by volcanologists.
Seismic activity, electromagnetism or geological deformation are patterns used to predict eruptions. But volcanologists there are looking for something else. They are sniffing out volcanic gas.
Mendez’s colleague Gustavo Garzon explains:
“It is essential to know the composition, concentration, content and flux of volcanic gases. Without those gases, there would not be volcanic eruptions. The gases create these eruptions.
There are different volcanic gases. But there is one especially important one: sulphur dioxide.
This gas is highly soluble when exposed to magma. So when magma comes to the surface, the gas is transported up. By measuring how much sulphur dioxide a volcano is emitting, we can calculate how much magma is coming up to the surface, and we can somehow predict how imminent an eruption is.”
Volcanologists face a painstaking climb to the volcano’s crater to manually monitor sulphur dioxide. But, says Garzon, it is not always possible:
“We are at an altitude of 5,200 meters, not far away from the crater. But we can’t carry on. It is too dangerous. Visibility is low, the snow is unstable. Conditions are difficult.”
So how can you measure sulphur dioxide safely?
On the volcano’s slopes, scientists say they have the answer.
They are working on NOVAC, a European Union research project aimed at providing real-time monitoring of sulphur dioxide in risky, almost inaccessible volcanoes.
Swedish physicist Bo Galle is the coordinator of the project. His team in Gothenburg has developed a prototype to measure the gas from a safe distance. He says the equipment needs to be both intricate and sturdy
“What we have done is take advantage of the last thirty years of developments in computing, optical spectroscopy and camera technology.
“The volcano is over there. When its gases come over here, we can measure them. Inside this unit there is a telescope, connected to a mirror that can rotate. So when the volcano gases come over here, the machine looks at different directions and scans through the volcanic gas plume. Data is sent to the box below to be read by computers. Data is then sent by radio to the observatories.
“It has been very challenging to build an instrument that can stand these extreme conditions. It is cold. There are big temperature fluctuations. There are ashes from the volcano. There are storms, there are acid rains. There is no infrastructure so everything has to be very robust. It is a very big effort to come up here to fix the system, even if the problem is small.”
Two other volcanoes in Colombia and more than 20 active, dangerous volcanoes around the world now have similar gas monitoring stations.
The network has already helped to correctly predict recent volcanic eruptions in Colombia.
Betty Silva is another engineer working on the volcanic slopes. She explains how sulphur dioxide levels indicate volcanic threat:
“Normal sulphur dioxide emissions are 1,000-3,000 tons/day in the Galeras volcano, for instance. When magma comes up, these emissions can skyrocket up to 15,000 tons. Then there is an obstruction. Magma builds up, it blocks all the holes. Gas emissions are cut considerably. It is at that moment, when no more sulphur dioxide is coming into the atmosphere, that a violent eruption may be imminent.”
Measurements from the volcano’s slopes are updated every five minutes and volcanologists use the data for risk assessment.
Gustavo Garzon told us that the technology makes his job safer:
“For years, we volcanologists have used different methods to assess the risks in volcanoes. Most of these methods were very risky. A few years ago, several volcanologists died in the Galeras volcano in southern Colombia, while they were measuring volcanic gases inside its crater. New methods like this one prevent us from entering high risk zones.
It also provides a continuous stream of data in real-time, which is crucial for predicting natural hazards linked to volcanic eruptions.”
The data is also crucial for potentially saving tens of thousands of civilian lives, as Fernando Salinas testifies:
“Now, scientists are doing a brilliant job monitoring dangerous volcanoes. If – at the time of the tragedy – we had had just a mobile phone, we would have all been saved. But we had nothing, no technology at all. We were blind. Completely blind until the very last moment. Now, new technology is helping protect people.”