Coastal ramparts vanish under a towering ocean surge.

It sounds like science fiction, but the mechanics behind a thousand-foot wave are grounded in real geologic processes. Landslides, subduction-zone quakes, or volcanic flank collapses could, under rare conditions, displace enough water to create a megatsunami capable of reshaping entire coastlines. Scientists have modeled these extremes not as predictions but as boundary tests of what the planet can do. Still, the data reveal a sobering truth—some U.S. states sit in positions so vulnerable that if such a wave ever occurred, they would simply cease to exist within minutes.



