Tsunami means tidal wave
Tsunami is a Japanese word and is a compound of Tsu (port) and Nami (Wave). These waves, which are often sky high, are caused by an undersea earthquake and can cause many kilometers further damage. The waves can move with high speed, because this does not happen on the surface but deep on the bottom of the sea, the waves lose almost no speed. A tsunami can be 1000 kilometers long and also take thousands of kilometres. The wave loses speed when the coast is reached, this causes houses to rise high waves, because of the enormous power the water comes up hundreds of meters into the country. A tsunami at sea is barely visible, a special warning system allows people to be warned on land. The Netherlands is reasonably safe because earthquakes in the Atlantic are barely preventable and if they are there they are not very powerful.