A team of researchers from Nokia Bell Labs used an existing 4,400 km telecommunications fiber optic cable between Hawaii and California as a huge seismic detector array, equivalent to 44,000 seismic stations spaced 100 m apart; the team presented the results at the annual meeting of the American Geophysical Union[1]. The method measures the small shifts of light in optical fibers (Distributed Acoustic Sensing, DAS) that occur as the seafloor deforms, and translates the fiber's internal errors into thousands of sensors across the cable[1][3]. The main technical problem is the light amplifiers (repeaters) placed approximately every 75 km that attenuate the bounced signals; the team has developed a way to use these amplifiers for the return fibers and thus recover reflections from even the most remote sections of the cable[1]. During the tests, the cable picked up the signal of a magnitude 8.8 earthquake off Kamchatka, as well as the faint signature of the following tsunami wave, which slightly deformed the sea surface[1]. The authors demonstrated that by analyzing these displacements, a dense array of "strain" gauges can be obtained suitable for imaging the Earth's interior and monitoring the seafloor and the ocean above it[1]. The work demonstrates the potential for extending the existing network of undersea cables (over 1.2 million km worldwide) into a large-scale seismic and environmental network without the need to install new sensors[4][5].