Berkeley scientists propose to transform existing underwater fiber cables into a network of seismic activity measuring devices. Most of the data currently collected by seismologists comes from land-based instruments, which means that there is not much information about ocean activity.
"Any instrument that goes into the ocean, even just 50 kilometers offshore, will get very useful information," says study coordinator Nathaniel Lindsey. The solution of transforming the underwater cable structure comes because it is quite complex and expensive to place, maintain and access measuring instruments with the required precision.
Lindsey's team proposes to use the scattering and distortion of light that travels on fiber optic cables and carries data. Monitoring these distortions, which occur exactly where the cables bend and to what extent, sometimes with only a few nanometers, allows seismic activity to be detected with a high degree of accuracy. Measurement is achieved using a technique known as DAS, Distributed Acoustic Sensing, which treats each cable as a series of thousands of motion sensors, reports Tech Crunch.
Jonathan Ajo-Franklin of the Berkeley National Laboratory says that "this is the first time anyone has tried to use offshore fiber optic cables to look at such oceanographic signals."
The team will continue to work to understand if any measured distortion is due solely to seismic phenomena or if there is any other justification. If successful, the experiment should be to use increasingly large cables as research tools.