How an earthquake causes a tsunami

  1. During an underwater earthquake, part of the ocean floor moves suddenly up or down either side of a fault line.
  2. The water above the plate moves suddenly up or down, creating a wave.
  3. This wave spreads out from where the earthquake hit, travelling at high speeds.
  4. As the wave reaches shallower waters it becomes taller, eventually crashing into land.

How to spot a tsunami