The Ocean Floor Is Now an Earthquake Alarm

Nokia Bell Labs and UW transform Oregon's fiber-optic cables into full-length seismic sensors without adding a single new device

1 May 2026

Researchers have turned existing fiber-optic cables beneath the Pacific Ocean into continuous earthquake-detection systems, a development that could significantly expand seismic monitoring along one of North America's most hazardous fault zones. Scientists from the University of Washington and Nokia Bell Labs announced in March 2026 that they had successfully deployed distributed acoustic sensing across two submarine cables off the Oregon coast, covering their full lengths for the first time. The work was published through the National Science Foundation's Ocean Observatories Initiative.

Distributed acoustic sensing works by transmitting pulses of light through fiber-optic cables and measuring the faint signals scattered back by microscopic imperfections in the glass. Vibrations along the cable, whether from seismic waves, passing ships, or dragging anchors, alter those backscattered signals in ways that can be precisely mapped. Earlier applications of the technology were constrained to the first 65 to 95 kilometers of a cable, beyond which signal degradation rendered the data unusable. The Nokia Bell Labs system extended that range by routing light through loopback couplers installed at existing repeater stations within the cables, reaching 480 kilometers along the northern cable and 350 kilometers along the southern one.

Those cables run across the Cascadia Subduction Zone, a seismically active region capable of producing major earthquakes and tsunamis, where permanent seafloor instruments remain scarce. Zoe Krauss, a researcher at the University of Washington, described the system as potentially transformative for offshore earthquake monitoring and early warning capabilities serving communities along the West Coast.

Yet the technology's applications extend beyond seismic science. Officials and analysts have noted that the system can also detect vessel movements and physical disturbances along cable routes, capabilities of growing relevance as governments in the United States and Europe move to strengthen protections for subsea communications infrastructure against both accidental damage and deliberate interference.

The experiment ran from November 2025 through January 2026 and generated 3.9 terabytes of data, which researchers made freely available. No new hardware was placed on the seafloor; the entire system operated through modifications to repeater technology already in place. With more than 100 new submarine cable systems expected to come online globally this year, analysts said the results could shape how subsea infrastructure is designed and regulated in the years ahead.