In Sicily drones predict eruptions

Researchers are employing new autonomous drone technology to monitor volcanic activity in Sicily, seeking to improve the accuracy and safety of eruption predictions. On the Aeolian island of Vulcano, teams from the Technical University of Munich (TUM) have begun deploying specialized systems to measure gas concentrations, which serve as critical indicators of underground volcanic processes.

The TUM research team, led by Marius Schaab and supported by Prof. Achim Lilienthal, utilizes a system that relies on a ground-based laser mounted on a portable cart. This laser tracks a drone equipped with a reflector. As the drone traverses a predefined path for 10 to 15 minutes at a distance of up to 60 metres from the laser, the beam passes through volcanic gas plumes. The reflected light is slightly absorbed by gases, such as carbon dioxide, allowing an algorithm to generate a tomographic map of gas distribution. This method effectively separates volcanic emissions from background signals generated by surrounding soil and vegetation. According to researchers, this process boasts a measurement error of about 5%.

A separate team from Johannes Gutenberg University Mainz, led by Prof. Thorsten Hoffmann, employs drones fitted with onboard sensors. These devices fly directly into the volcanic plume, using photometric and electrochemical measurement cells to identify concentrations of gases and particles, including chlorine and bromine. These efforts aim to better understand how volcanic emissions affect the atmosphere and to detect shifts in gas composition — specifically the ratio of carbon dioxide to sulfur dioxide — that often precede eruptions. Because the solubility of these gases in magma depends on pressure, the composition of the escaping mixture offers insights into the activity occurring deep beneath the surface.

These aerial methods provide a significant safety upgrade over traditional ground-based monitoring. "Here we don't have a major risk of an imminent eruption but there are volcanoes where you can't reach the summit on foot," said researcher Tjarda Roberts, noting that drones allow scientists to bypass the dangers of entering corrosive, high-temperature gas plumes, some reaching between 100 and 140C, without the need for protective gear.

While gas monitoring continues, other researchers are simultaneously tracking seismic signals to forecast activity at Mount Etna. Recent findings from the National Institute of Geophysics and Volcanology suggest that monitoring the "b value", a parameter measuring the ratio of low- to high-magnitude earthquakes, can track magma movement within the Earth's crust. According to research published earlier this month, these seismic variations can precede geochemical anomalies, such as gas releases, by several months. This lead time is vital for Mount Etna, which is situated near the city of Catania and home to approximately 1 million people.

Mount Etna, an active volcano with an eruptive history spanning 500,000 years, remains under intense scrutiny following a recent eruption in June that sent clouds of gas and rock up to 4 miles into the air. The ultimate goal remains the automation of these mapping processes and the integration of artificial intelligence to interpret the data, creating a more robust early-warning system for volcanic regions.