Optical polarization–based seismic and water wave sensing on transoceanic cables

Waiting for earthquakes to call Instrumenting the vast ocean floor is difficult and expensive but important for monitoring earthquakes and tsunamis. Zhan et al. used the polarization of regular telecommunication traffic to detect earthquakes and water swells in a 10,000-kilometer-long fiber-optic submarine cable (see the Perspective by Wilcock). The deep-water Curie cable is not as noisy as terrestrial counterparts, allowing the authors to detect strain from the cable. Results from the 9-month observation period showed how current submarine fiber-optic cables can also be used as a geophysical tool. Science , this issue p. 931 ; see also p. 882