If it looks dangerous, send in the drones

Flying drones into volcanoes is becoming quite a thing.

Earlier this year, Cosmos reported how German and Russian scientists used satellite drone data to help document the lifecycle of the Bezymianny volcano in eastern Russia.

Now researchers led by University College London have used specially-adapted drones to gather data from the previously unexplored Manam volcano in Papua New Guinea (PNG).

They say their findings, published in Science Advances, show for the first time how it is possible to combine measurements from the air, Earth and space to learn more about how inaccessible and highly active volcanoes contribute to the global carbon cycle.

The project brought together volcanologists, aerospace engineers and other specialists from the UK, PNG, the US, Canada, Italy, Sweden, Germany, Costa Rica and New Zealand.

Manam, which has a diameter of 10 kilometres, is located on an island 13 kilometres off the northeast coast of the PNG mainland, at 1800 metres above sea level. Its last major eruptions between 2004 and 2006 devastated large parts of the island and displaced the population of some 4000 people to the mainland.

Previous studies have shown it is among the world’s biggest emitters of sulphur dioxide, the researchers say, but nothing was known of its CO₂ output.

Volcanic CO₂ emissions are challenging to measure due to high concentrations in the background atmosphere. Measurements need to be collected very close to active vents and, at hazardous volcanoes like Manam, drones are the only way to obtain samples safely. Yet beyond-line-of-sight drone flights have rarely been attempted in volcanic environments.

By employing miniaturised gas sensors, spectrometers and sampling devices that are automatically triggered to open and close, the team was able to fly the drone two kilometres high and six kilometres away to reach Manam’s summit, where they captured gas samples to be analysed within hours.

Calculating the ratio between sulphur and carbon dioxide levels in a volcano’s emissions is critical to determining how likely an eruption is to take place, as it helps volcanologists establish the location of its magma.

“Manam hasn’t been studied in detail but we could see from satellite data that it was producing strong emissions,” says project leader Emma Liu, from UCL. “The resources of the in-country volcano monitoring institute are small and the team has an incredible workload, but they really helped us make the links with the community living on Manam island.”

Following their fieldwork, the researchers raised funds to buy computers, solar panels and other technology to enable the community, which now has a disaster preparedness group, to communicate via satellite from the island, and to provide drone operations training to Rabaul Volcanological Observatory staff to assist in their monitoring efforts.