Mega Tsunamis | Wave Of Destruction

Over the last fifty years scientists have found in nature enough evidence of a previously unknown natural phenomenon that, although similar to "traditional" Tsunamis, may in fact cause an incomparable level of destruction along the coastlines. Such wave of huge proportions will be probably triggered in the Atlantic Ocean anytime in the next 500 years thus posing a daunting threat for the East Coast of America, North Africa and Europe.

Image: Mega-Tsunami: fiction picture gives an idea of wave height

Waves of this type are called Mega Tsunami. They are so great that they can reach several hundred meters in height, travel at the speed of a jet aircraft and get up to 12 miles (20 Kilometers) inland.

A mega-tsunami is an extremely rare and destructive phenomenon that strikes the world every few thousand years. Unfortunately, as seen in the documentary above, there is a concrete possibility that it will occur again in the near future. A mega-tsunami has almost unlimited power to cause utter destruction and there's nothing we can do to stop it. Even the most powerful waves, the tidal waves known to science by their Japanese name Tsunami, cannot create such destruction.

A mega-tsunami is an informal term to describe a tsunami with initial wave amplitude (height) much larger than usual tsunamis. Mega-tsunamis are several tens, hundreds, or possibly thousands of meters high and they are able to cross oceans and ravage countries on the other side of the world.

Generally, a tsunami is caused by an earthquake near the shore or underwater. Normal tsunamis usually originate from offshore earthquakes, submarine landslides and undersea volcanic activity, and range from barely perceptible waves to walls of water up to 300 feet high. The biggest submarine earthquakes can shift the ocean bed up or down by around 10 metres and that produces tsunamis on that sort of scale, but not very much bigger.

Normal tsunamis created by an earthquake on the ocean floor have only small wave heights while off shore. They also have a very long wavelength (often hundreds of kilometres long) and they generally pass unnoticed at sea, forming only a slight swell usually of the order of 30 cm (12 inch) above the normal sea surface. However, the height of normal tsunami waves increases dramatically when they reach land as the base of the wave pushes the water column on top of it upwards.

By contrast, something massive is needed to create waves with such a great height in the case of a mega-tsunami. So, what kind of event can create a mega-tsunami? Unlike usual tsunamis, mega-tsunamis are caused by giant landslides and other impact events such as volcanic eruptions or huge asteroids crashing into the sea. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water.