Scientists from the Institute of Geophysics at ETH in Zurich, Switzerland have developed a way to monitor impending earthquakes and tsunamis with fiber-optic infrastructure. Tech Briefs reported that ETH and the Swiss Federal Institute of Metrology found that every single wave of a magnitude 3.9 earthquake registers in the noise suppression system of fiber-optic networks. Using active phase noise cancellation (PNC) to measure seismic tremors is a cost-effective method that could help less developed countries with early detection.
“We’re taking advantage of a function that existing fiber-optic infrastructure already performs: we obtain the vibration data from the active noise suppression system, which has the job of increasing the accuracy of the signals in optical data communication,” said Geophysics Professor Andreas Fichtner. He explained that the objective is to store and evaluate active noise suppression data.
How does it work? Scientists look for “noise” in the PNC of data communication systems. If optical fibers are perturbed (even slightly), this means there are deformations of the Earth’s surface due to earthquakes, water waves, differences in air pressure, and human activity. Each deformation shortens or lengthens the fiber slightly, causing a photo-elastic effect, which causes the speed of light in the fiber to change.
Tech Briefs reported that the PNC data can be used to determine an earthquake’s location, depth, and magnitude accurately. According to Fichtner, this same principle can also be applied to tsunamis.
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