Researchers have made significant strides in improving earthquake early warning systems (EEW) by utilizing disused fiber optic cables originally intended for telecommunications to monitor offshore seismic activity. The scarcity of offshore seismic stations in densely populated coastal regions, which are often prone to earthquakes, has been a challenge for EEW systems.
In a study published in The Seismic Record, Jiuxun Yin, a former researcher at Caltech, and his colleagues demonstrated the potential of repurposing these undersea fiber optic cables.
The technique they employed, known as Distributed Acoustic Sensing (DAS), leverages the imperfections within extended optical fibers, effectively converting them into thousands of microscopic seismic sensors. They collected seismic data from 8,960 channels along a 50-kilometer undersea telecommunications cable connecting the United States and Chile, estimating the magnitudes of both offshore and onshore earthquakes that occurred during the research period.
Jiuxun Yin noted that the offshore location of the DAS array significantly improved the speed of earthquake detection, eliminating the need to wait for seismic waves to reach land-based stations. This technology holds promise for regions like Chile, which faces a high seismic risk due to its active subduction zones and history of significant earthquakes. Offshore EEW systems could play a vital role in safeguarding lives and property in such areas.
The research team used deep learning artificial intelligence models to identify earthquake waves in the DAS data efficiently. Yin emphasized the importance of gathering more data, especially from larger magnitude earthquakes, to develop and test EEW algorithms effectively. They also stressed the need to understand how DAS instruments respond before implementing a real-time EEW system.
One of the significant advantages of this approach is that it can be implemented without affecting telecommunications data transportation, thanks to technological advancements. There are over 1,500 cable landing stations worldwide, offering exciting research opportunities for the future. Jiuxun Yin expressed a desire for collaboration with cable owners, environmental agencies, and policymakers to expand the use of DAS-based EEW systems for the benefit of coastal communities.
The research showcases an innovative and cost-effective solution to enhance earthquake early warning capabilities in regions prone to seismic activity, potentially saving lives and reducing damage in densely populated coastal areas.