Around 600 million people live dangerously near one of the Earth’s 500 active volcanoes. Thanks to Cambridge scientists – who over the past 15 years have pioneered new techniques for monitoring volcanic activity – communities across the world are able to make better decisions to protect lives and property.

[We] rely heavily on these kinds of monitoring data ... to make decisions on hazard mapping, exclusion zone management, land use planning, development and investment

Monserrat Disaster Management Coordination Agency

Because they were smaller, lighter, cheaper and less power hungry, the new devices could form the basis of a worldwide monitoring system

Safer communities

From Etna and Stromboli, Italy to Iceland’s Eyjafjallajokull and Monserrat’s Soufriere Hills volcano, techniques developed in Cambridge have revolutionised volcano monitoring networks across the world, helping communities better understand the changes that can foreshadow a major eruption.

The application of ultraviolet (UV) spectroscopy pioneered at Soufriere Hills by Professor Clive Oppenheimer of the Department of Geography and Dr Marie Edmonds of the Department of Earth Sciences now forms the basis of scanning UV spectrometer networks at 20 other volcanoes worldwide.

By providing better data to decision makers, their research is helping keep vulnerable communities safer from the devastating effects of volcanic eruptions. And in Monserrat, partially destroyed when Soufriere Hills began erupting in 1995, Cambridge science is providing reliable evidence to inform planning decisions as new infrastructure is developed.

Bubbling under

Around 600 million people live near the world’s 500 active subaerial volcanoes. At any one time, there will be five volcanoes starting to show new activity and another 10 or 20 with ongoing activity.

The dangers active volcanoes pose are obvious. The ash, gases and lava they emit during an eruption can destroy lives, as well as property, infrastructure and agriculture. The financial impact is enormous. The 2010 eruption of Icelandic volcano Eyjafjallajokull caused massive disruption to international air traffic, costing the aviation industry $1.7 billion. And when the Soufriere Hills volcano on Monserrat erupted in 1995, more than 8,000 people – two-thirds of the island’s population – were displaced.

Despite this, understanding which changes in volcanic activity signal that an eruption is more likely has been a challenge for those who study volcanoes, as well as those who live near them.

Mountain of evidence

Oppenheimer and Edmonds have spent years studying the gases volcanoes emit before and during eruptions. Working at Soufriere Hills, they recorded levels of sulphur dioxide (SO2) and hydrogen chloride (HCl) to understand how these key gases could be used to better predict volcanic eruptions.

They discovered that SO2 flux is an effective proxy for deep magma supply, and changes in HCl levels a proxy for eruption rate. They also found that monitoring SO2 emissions is essential to assessing volcanic hazard, and that because these emissions vary so widely, continuous monitoring vital.

Chemistry, however, was only half of the story. During their work, Oppenheimer and Edmonds realised that vulcanologists also needed better ways of monitoring these gases.

From the 1970s, gas monitoring at volcanoes relied on the so-called Correlation Spectrometer (COSPEC). Cumbersome and costly, the Cambridge team sought something new, and when in the early 2000s cheap, miniaturised UV spectrometers came onto the market, they recognised their potential.

After adapting the UV spectrometers to monitor volcanic gases, they tested them alongside the COSPEC at Soufriere Hills and at Masaya volcano in Nicaragua. Their results revealed that the UV monitors were just as accurate. And because they were smaller, lighter, cheaper and less power hungry, the new devices could form the basis of a worldwide monitoring system.