This isn’t a wave that goes up and down. The entire ocean level seems to rise 7 feet, then it just keeps coming... and coming... and coming.
Imagine if the sea level suddenly rose by seven feet. The force can wash away an entire town and kill thousands.
Thanks. I didn’t think about it that way.
More to the point... The 6 ft tsunami height is the height of the wave AT SEA. As the wave approaches shore and gets into shallower water it will build up and break several times higher than that.
Another difference is the period. Instead of a normal wave with a period of only a few seconds... A tsunami could have a period of several minutes. That is, the wave comes in, and just KEEPS coming...