flóðbylgjum

Flóðbylgjum, commonly known as tsunamis in English, are a series of extremely large waves created by a sudden displacement of a large volume of water, typically in an ocean or a large lake. The most common cause of tsunamis is underwater earthquakes, particularly those that occur at subduction zones where one tectonic plate slides beneath another. Other triggers can include volcanic eruptions, landslides that fall into the water, and meteorite impacts.

When a tsunami-generating event occurs, it displaces the water column from the seabed to the surface. In the deep ocean, tsunami waves are often imperceptible, with wavelengths that can be hundreds of kilometers long but wave heights of only a meter or so. Their speed in deep water is very high, comparable to that of a jet airplane, traveling at speeds of up to 800 kilometers per hour.

As a tsunami approaches shallower coastal waters, its speed decreases significantly, but its energy is compressed into a much shorter wavelength, causing the wave height to increase dramatically. This phenomenon can result in towering waves that inundate coastal areas, causing widespread destruction. The term "flóðbylgja" directly translates to "flood wave" in Icelandic, aptly describing the destructive force of these events. Unlike normal waves that break and dissipate quickly, a tsunami is more like a rapidly rising tide or a wall of water that can surge far inland.