Final answer:
As waves reach shore, they refract or bend towards the shoreline due to the decrease in water depth. The degree of bending depends on the angle of incidence and the change in water depth. Waves focused by refraction can occur under various depth and shoreline conditions.
Step-by-step explanation:
As waves reach shore, the water depth decreases and the energy of the wave is compressed into a smaller volume. This compression causes the wave rays, or crest-lines, to refract or bend towards the shoreline. The degree to which the waves bend depends on the angle of incidence and the change in water depth. When the waves approach the shoreline at an angle, they refract and the wave rays focus towards shallower depths.
For example, if the shoreline gradually slopes from deep to shallow, the wave rays will bend towards the shallower water, focusing the wave energy in a narrower area. This can result in higher and more powerful waves breaking in that specific area.