Japan has completed the world’s most advanced undersea earthquake and tsunami detection system—3,500+ miles of fiber-optic cables linking 186 observatories across the ocean floor. It’s designed to warn citizens and infrastructure minutes ahead of massive quakes and tsunamis, a leap forward after the devastating 2011 disaster. The newly completed S-net and N-net networks allow near-instant detection of seismic activity along entire subduction zones. Meanwhile, Cardiff University in Wales has adapted nuclear explosion detectors to spot tsunamis faster than ever. But experts warn that the U.S. remains woefully behind—especially on the Pacific Northwest’s Cascadia megathrust fault. With just one cable and three sensors, the U.S. could face catastrophic consequences from a future magnitude 9.0 quake. Japan’s model could be the blueprint the rest of the world urgently needs.
