The worldwide network of telecommunications cables lying on the bottom of the world’s oceans offers unique potential for scientific use if the fibre-optic cables themselves are used as or equipped with sensors. Based on this, the GFZ Helmholtz Centre for Geosciences in Potsdam and the GEOMAR Helmholtz Centre for Ocean Research Kiel are now setting up the research infrastructure SAFAtor (SMART Cables And Fiber-optic Sensing Amphibious Demonstrator), that can be used to monitor the world’s oceans. It will be included in the portfolio of the major Helmholtz infrastructures and funded by the Helmholtz Association with 30 million euros as a strategic development investment. Among other things, the plan is to equip initially one demonstrator cable with appropriate sensor technology before deploying it in the deep sea in order to obtain important real-time data on climate and geological hazards. So far, almost no data exists from the seafloor. SAFAtor aims to close this data gap in the oceans. GFZ scientist Prof. Dr Fabrice Cotton, head of GFZ Section “Seismic Hazard and Risk Dynamic” is the project lead (PI). Co-PIs are GFZ researchers Prof. Dr Charlotte Krawczyk, Director of GFZ-Department Geophysics, who will take over the lead after two and a half years as scheduled, and Prof. Dr Frederik Tilmann, Head of GFZ Section “Seismology”, as well as Prof. Laura Wallace, Head of GEOMAR Research Unit “Marine Geodynamics”. The SAFAtor project will run for five years and will start with a kick-off meeting at the GFZ on Potsdam’s Telegrafenberg on 5-6 March 2025.
Closing the ocean data gap
Seventy per cent of our planet is covered by oceans. Compared to the continents, little scientific data can be obtained there, since the ocean floor in particular is difficult to access and therefore insufficiently equipped with measuring stations. “There is a huge gap in our observational data, which makes it difficult for us to better understand the effects of climate change on the oceans or the causes of geological hazards like earthquakes, tsunamis or volcano eruptions,” says Charlotte Krawczyk. She is the director of the GFZ Department of Geophysics, heads the Section “Geophysical Imaging”, and was instrumental in initiating and advancing the project. Krawczyk: “We want to close this gap with SAFAtor.”
How SAFAtor works
SAFAtor stands for “SMART Cables And Fiber-optic Sensing Amphibious Demonstrator”. Over the next five years, the project partners GFZ and GEOMAR want to equip an undersea telecommunications cable with special sensor technology. To this end, around 40 sensor stations will be attached to the cable before it is laid, at a distance of about 20 to 30 kilometres, preferably at the repeater stations. These will continuously supply real-time data on temperature, pressure and ground movement. It must be demonstrated that telecommunications traffic is not disrupted. Fibre-optic cables equipped with intelligent sensor technology are also known as SMART (Science Monitoring and Reliable Telecommunications).
“Telecommunications cables run across the oceans and have to be replaced every 25 years. If we use SMART cables for this, we will be able to achieve simple and comparatively inexpensive sensor coverage of the ocean floor and coastal areas,” says Fabrice Cotton, who is coordinating the entire project as topic spokesperson on geological hazards for the Helmholtz Association. “The design of the project was a great team effort involving researchers from different disciplines and different age. The European and international integration of this project was taken into account from the outset, and the project is supported by about twenty international organisations,” adds Cotton. He also heads the European GeoINQUIRE project, which has initiated the first developments for disseminating this novel data to the scientific community.
Coverage of the deep sea and coastal areas
The exact route of the SAFAtor cable has not yet been determined. Possible regions worldwide are currently being explored, including the Mediterranean, the Arctic and off New Zealand. The SAFAtor cable can then serve as a blueprint for future projects, thus advancing international initiatives that want to establish this measurement system on other cables by providing practical and scientific experience.
In addition, permanent coastal monitoring is planned at three selected observatories: near the seismically active North Anatolian fault zone, which threatens the city of Istanbul, at Etna, one of the most active European volcanoes, and at the northern Chilean subduction zone, where strong earthquakes occur regularly. The fibre-optic measurement principle is used for coastal monitoring, in which the cable itself serves as a sensor. With this technology, the light pulses in individual glass fibres can be used to measure even the smallest ground movements, such as those triggered by earthquake waves.
All newly acquired cable data will be made available centrally. To this end, a data service is being set up at the GFZ that will also serve as a platform for future cable data. “The Helmholtz Association thus has the unique opportunity to take a leading global role in the development of these tethered sensor systems and in the dissemination of the new observational data,” says Frederik Tilmann, Co-PI at GFZ.
New climate, ocean and geological data
The new data have the potential to revolutionise our understanding of ocean currents and the role of the oceans in climate change. At the same time, they will be of outstanding importance for understanding geological hazards like earthquakes, tsunamis, landslides, volcanic eruptions and significantly reduce early warning times for extreme events. In addition to these core applications, the data will also be used to study marine ecosystems.
Laura Wallace from GEOMAR says: “Real-time monitoring of processes on Earth is the key to protecting society from natural hazards and the effects of climate change. With the help of SAFAtor, we can provide high-resolution data not only for earthquake and tsunami studies, but also for oceanography and climate science, with an infrastructure that has a minimal ecological footprint.”
Expertise of the participating Helmholtz centres
SAFAtor draws on the GFZ’s many years of experience in operating global and regional observatories and in research data management of large data sets. The researchers at the GFZ will therefore be primarily responsible for the expansion of the observatories in the coastal area, but will also be involved in the selection and equipping of a demonstrator cable with SMART sensors. The GFZ will also provide the infrastructure to process and archive the newly acquired data and make it accessible under the FAIR principles. FAIR stands for findable, accessible, interoperable and reusable.
GEOMAR, with its expertise in the development of submarine technologies, will play a leading role in the integration of the necessary SMART sensor technology into deep-sea cables. The associated project partners – the Helmholtz centres AWI and Hereon – are providing their COSYNA underwater infrastructure near Helgoland for development purposes. SAFAtor also receives broad national and international support from scientific consortia and institutes, industry and network operators.
