How do waves get their shape?



I’m talking about waves in water. Oceans, lakes, pools, etc. How do they get their shape, and also why does that shape change when they come to shore?

In: Physics

Even though waves *look* like purely surface effects on oceans, lakes, etc., the interesting fact is that the wave actually affects the water all the way down from the surface to the solid seabed. *The total water depth* affects the surface wave’s height and speed.

Shallower water means slower (and taller) waves. Near land, this distorts the wave shape and makes it crash — a wave crest is literally speeding beyond its own base, in the shallows near shore.

Higher slower waves near shore are a particular problem for people dealing with tsunami waves: