Tsunamis are caused by energy originating underwater from a volcanic eruption, a submarine landslide, or, most commonly, an earthquake on the ocean floor.

1. For example, the tectonic plates of the Earth’s surface slip, releasing a massive amount of energy into the water.
2. This energy travels up to the surface, displacing water and raising it above the normal sea level.

3. Gravity pulls that energy back down.

4. As a result, the energy ripples outwards horizontally.
Thus, the tsunami is born, moving at over 500 miles per hour.

From the TED-Ed Lesson How tsunamis work - Alex Gendler

Animation by Augenblick Studios