Megatsunami
A megatsunami is a very large wave created by a large, sudden displacement of material into a body of water. Megatsunamis have quite different features from ordinary tsunamis. Ordinary tsunamis are caused by underwater tectonic activity and therefore occur along plate boundaries and as a result of earthquakes and the subsequent rise or fall in the sea floor that displaces a volume of water. Ordinary tsunamis exhibit shallow waves in the deep waters of the open ocean that increase dramatically in height upon approaching land to a maximum run-up height of around 30 metres in the cases of the most powerful earthquakes. By contrast, megatsunamis occur when a large amount of material suddenly falls into water or anywhere near water. They can have extremely large initial wave heights ranging from hundreds and possibly up to thousands of metres, far beyond the height of any ordinary tsunami.
