Why isnt a tsunami a tidal wave?
Tsunami is a Japanese term meaning “harbour wave”. At sea a tsunami appears as a very small wave, probably less than 1m high. It’s when they reach shore that they grow higher and flow inland. They cause the most damage in enclosed basins (like harbours) where the large volume of water introduced cannot escape and sloshes about destroying everything in the basin. Hence “harbour wave”. They were also called tidal waves because on a gently sloping shoreline an approaching tsunami sucks the water away from the land exposing the seafloor. This is much like the effect of a very low tide – hence “tidal wave”. However, a tsunami has nothing whatever to do with the normal tides.
