Drones can be helpful in predicting volcanic eruptions and averting disasters

There are often up to 50 volcanoes on Earth that are actively erupting at any given time. Many of these volcanoes release heated gases, such as steam and carbon dioxide, rather than lava. While risky, collecting these gases is essential to understanding the enigmatic behavior of volcanoes.

Collecting gas samples ejected from volcanoes is dangerous, but now drones make it safer and easier than ever.

Fiona D’Arcy, a graduate student in geosciences at McGill University, has regularly visited gas-laden volcanoes to capture them just before, during, or after an eruption.

She has worked with other scientists and engineers to measure volcanic gases using a variety of devices attached to drones.

She said: “Our latest research uses drones to capture volcanic carbon dioxide at Poás Volcano in Costa Rica. We measured the carbon isotopes in this carbon dioxide and discovered a pattern in the way these chemical fingerprints change during different states of activity.”

Where are drones helpful in exploring volcanoes?

Carbon dioxide is everywhere: in the air we breathe, in vehicle exhaust and dissolved in magma. In volcanoes, it escapes from the magma to the surface through fissures and hydrothermal systems (such as the geysers in Yellowstone National Park), seeping through the ground or escaping in a gas cloud.

Researchers can now evaluate the stable carbon isotope ratio, a characteristic chemical composition that reveals the source and route of CO2 reaching the surface, by taking a sample of this volcanic carbon.

Every volcano around the world produces a unique spectrum of these carbon isotopes, which change as the volcanic system changes.

It used to take a while to get each sample because researchers had to descend into a crater, putting them in danger for every second they were there. As a result of the development of these devices, researchers have started using unmanned aerial systems (UAS) or drones in dangerous places.

How are drones used?

To do this, the researchers connected gas sensors to the on-board communication systems of the UAS via switches and electronic components. The volcanic CO2 would be sucked in through a network of pipes with the help of a pump and sensors that warn the pilots when they hit the gas plume. The pilot can choose when and where to take the gas sample with a simple switch on the remote control while staying at a safe distance.

Sharing her experience using drones to study Poás Volcano in Costa Rica, D’Arcy said: “We arrived in Costa Rica in April 2019 with our shiny new drone setup that we launched on the rim of Poás Volcano to which crashed almost immediately. Luckily, our team came up with a quick fix for our second drone – a pump and switch hanging from the drone in a laundry bag. It worked perfectly.”

She explained: “To avoid further casualties, we got close to the crater and flew our array directly over it. Later that day, we examined the stable isotopes of carbon in our drone samples and in the samples we collected from the ground. After we accounted for mixing with normal air in the drone samples, the two results were strikingly similar. Our drone assembly worked!”

A pattern emerges

When D’Arcy began compiling data on all of the carbon isotopes measured at Poás Volcano in the past, a trend emerged of how the balance of the isotopes shifted when the volcano behaved differently.

Carbon isotopes slipped to lighter levels during eruption phases, when Poás performed wet blasts releasing particularly hot, sulfur-rich gas. Meanwhile, during quieter periods when the volcano was sealed, the isotope balance rose to heavier levels.

D’Arcy said: “With this new finding, we could look even further back and merge our data with isotopic data from older activity. We have seen this pattern repeat itself, with carbon isotopes alternating between heavy and light values ​​over the last 20 years of activity at Poás.”

There were relatively high readings when the volcano was sealed and relatively light readings when the volcano was open.

Now researchers know exactly what warning signs to look for in future carbon isotope samples taken from the volcano to know if the volcano is about to erupt.

future research

D’Arcy noted, “Thanks to drones, we’ve captured the first CO2 from Poás Volcano since 2014. Volcanic gases sampled prior to our work were all hand sampled by brave volcanic scientists who descended into the Poás crater.”

With the advent of gas-sampling drones, carbon dioxide can be sampled at volcanoes more frequently. This will fill in the gaps in the timeline and help us understand and predict eruptions.

(With inputs from PTI)

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