A normal wave is formed as a result of friction between the surface of the sea and wind, whereas a tsunami wave is formed due to an earthquake displacing a body of water. A normal wave has an approximate height of 2 metres compared to a tsunami wave which has an approximate height of 30 metres. A tsunami wave also has a much greater speed than a normal wave. Lastly, a tsunami wave has a greater crest distance (200km) compared to a normal wave (100m).