Born from earthquakes, racing faster than a jet, arriving as a wall of black water.
In the open ocean a tsunami passes eerily silent — ships barely feel it. But as it shoals, survivors describe a roar like a jet engine inside the sea. Its infrasound (<20 Hz) outruns the wave at the speed of sound, detected by microbarometers thousands of kilometres away before the water arrives.
A tsunami is a series of ocean waves generated by the sudden displacement of water — most often by undersea earthquakes of magnitude 7.5 or greater, but also by landslides and volcanic collapse. In deep water the wave is low and fast, almost invisible; near shore it slows, stacks up and strikes as a rising wall of water, not a breaking surf. The first wave is rarely the largest, and the ocean may drain seawards minutes before impact.