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USGS CMG InfoBank: Wave Refraction

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Comment: 07:23 - 08:28 (01:05)
Source: Annenberg/CPB Resources - Earth Revealed 24, Waves, Beaches and Coasts
Keywords: wave, refraction, shoreline, "shallow water", "wave velocity", "deep water", bay, headland

Our transcription: Fortunately, tsunamis are not everyday events, but even ordinary waves have some impact on the shoreline.
One very important process at work here is "refraction," the bending of wave fronts as they approach the shore.
When a wave approaches the shore at an angle, the near-shore stretch of wave front reaches the shallow water first and is, therefore, slowed down first.
This local decrease in velocity causes the wave front to bend or refract because the deeper water portion of the wave continues to move at its original speed.
As a consequence of this refraction, the waves near shore tend to approach the coast nearly head-on while those in deeper water continue along their original course.
Wave refraction has its greatest effect on irregular shorelines with deep bays and projecting headlands.

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Page Last Modified: Thu Oct 31 04:27:53 PDT 2013  (chd)