Scientists at the National Physical Laboratory (NPL) have discovered a new technology that can turn undersea power and communications cables into arrays of environmental sensors, opening the door to widespread ocean monitoring.
The survey results are science magazinecould revolutionize the way we monitor our planet by providing real-time environmental data from the ocean floor.
Despite advances in sensor technology, much of the world's ocean remains unmonitored due to the high cost and technical challenges of installing and maintaining permanent undersea sensors. This lack of monitoring leaves large gaps in geophysical data and limits our understanding of the Earth's structure and dynamic behavior.
Tsunami detection
Previous research by NPL and its partners demonstrated that submarine cables can be repurposed as sensors to detect underwater earthquakes. However, each cable could only act as a single sensor, and measurements were limited to changes over the length of the cable.
New research shows that a given cable can be transformed into not just one sensor, but an array of sensors. The team, which included researchers from the University of Edinburgh, the British Geological Survey, the National Institute of Metrológica Richerca and Google, tested the technology on a 5,860km undersea fiber-optic link between the UK and Canada, provided by EXA Infrastructure.
The research team detected earthquakes and ocean signals such as waves and ocean currents in individual spans between repeaters across the transatlantic connection. Each fiber optic span served as a sensor, and up to 12 sensors were implemented along the cable.
By turning underwater communications infrastructure into a vast array of geophysical sensors, this groundbreaking research could enable the monitoring of vast areas of the ocean floor that are currently unmonitored.
Furthermore, this study suggests that this method could be used for tsunami detection. This technology could provide vital additional warning time and potentially save lives by enabling real-time detection of tsunami-inducing earthquakes close to their offshore epicenters. The researchers now plan to test the method on multiple submarine cables, including those in seismically active regions such as the Pacific Ocean.
We spoke to Giuseppe Mara, lead researcher at NPL, about this new technology.
Is it theoretically possible to do triangulation using cables?
yes. Similar to land-based seismometers, multiple cables can be used to locate the epicenter of an earthquake. Since each cable is “translated” into an array of sensors rather than a single sensor, it is already possible to determine the focal area with one cable, and the resolution can be improved using multiple cables.
Can I use cables to transfer collected data at the same time?
Yes, data traffic can be on other channels on the same fiber. This was indeed the case during our testing and is an important aspect for extending this technology to many cables around the world. We used cables for intercontinental internet traffic. No proprietary cables were used for this study.
Or can it only be used as a sensor?
As per above, the same cable can be used for both data and sensing. No changes are required to the underwater cable infrastructure, and thus this technology could be the first viable solution to the lack of data from the seafloor (due to the lack of permanent seafloor sensors).
