Although volcanic eruptions can strike when least expected, they sometimes give off warning signs that can be captured by advanced technology. One innovative way to monitor eruptions is now being put to the test at the Reykjanes Peninsula, a hotbed of volcanic activity in Iceland. In a new study, researchers have reported the successful progress of an eruption warning system that uses distributed acoustic sensing (DAS), which can anticipate volcanic activity through magma movements beneath the surface.The study, published in Science, demonstrates how DAS sensors at the Reykjanes Peninsula can give the public warnings on lava eruptions up to 30 minutes in advance. The key to this method is in fiber-optic cables that react to disturbances underground. With a system to monitor cables, scientists are tapping into unseen volcanic data like never before.Iceland's Volcanic EruptionsIceland lies in a unique position as part of the Mid-Atlantic Ridge, a 10,000-mile-long mountain chain that represents the boundary between the North American and Eurasian tectonic plates. While most of it is submerged deep underwater, portions of the ridge rise from the ocean and form islands (like Iceland itself). This setting gives the country a diversity of geologic features, from massive faults to hot springs and geysers. Being on the Mid-Atlantic Ridge also exposes parts of Iceland to volcanic eruptions. The Reykjanes Peninsula has seen a significant increase in eruptions since 2021 and has experienced eight eruptions of lava since November 2023. Although the risk of injury or death from volcanic activity is relatively low, recurring eruptions near the town of Grindavík have forced people to evacuate their homes year after year.Sensing Underground Vibrations For the past few years, an international team of researchers has been working toward a solution to catch volcanic activity before it can impact the public. This collaboration led to the development of a DAS system focused on an underground fiber-optic cable. "The deployment was extremely fast," said Jiaxuan Li, the study's first author and a geophysicist at the University of Houston, in a statement. "We were able to set up our system on a 100-kilometer-long fiber cable within 10 days after a substantial magma intrusion event on November 10, 2023. About a month later, we recorded the first eruption with our system.”The DAS system entails directing lasers into unused underground cables; when vibrations pass through the cables (during an earthquake, for example), the lasers go through what is called a “phase-change,” allowing researchers to collect data on seismic waves.A New Warning SystemThe system can be applied to underground volcanic activity as well. As magma moves upward to surge above the surface, it warps and compresses the ground. The researchers say cable sensors can measure changes in the ground much more precisely than GPS or satellite imaging.Data from the sensors set up in the Reykjanes Peninsula have allowed researchers to create an early-warning system that could inform the public of an eruption 30 minutes to several hours before it occurs.The system has already helped seismologists at Grindavik detect volcanic activity and understand how magma behaves underground. Since Iceland is expected to enter a period marked by more frequent eruptions, increasingly reliable volcano warnings are needed now more than ever. “There is a lot more work to do, and all volcanoes are different, but DAS provides us a new capability to see things we couldn't before,” said Zhongwen Zhan, a geophysicist at the California Institute of Technology whose laboratory conducted the research. “Our project is also a great example of the power of international collaboration."Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:UNESCO. The Mid-Atlantic RidgeEuropean Geosciences Union. What is Distributed Acoustic Sensing?Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.