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Waves play an important role in the way coastal ecosystems function, and also provide tourism dollars because of their draw for surfers.

Sculpting seawater into crested shapes, waves move energy from one area to another. Waves located on the ocean’s surface are commonly caused by wind transferring its energy to the water, and big waves, or swells, can travel over long distances.

When waves crash onshore they can make a significant impact to the landscape by shifting entire islands of sand and carving out rocky coastlines. Storm waves can even move boulders the size of cars above the high tide line, leaving a massive boulder hundreds of feet inland. Until recently, scientists attributed the placement of these rogue boulders to past tsunami damage, however, a 2018 study upended this notion by carefully recording the movement of boulders along a swath of rocky coastline in Ireland over a time period in which no tsunamis occurred. In addition to over 1,000 mid-sized boulders, many reaching over 100 tons in weight, scientists recorded the movement of a 620-ton boulder (the same weight as 90 full-sized African elephants), showing that storm waves moved it over 8 feet (2.5 meters) in just one winter.

The anatomy of a wave

A wave forms in a series of crests and troughs. The crests are the peak heights of the wave and the troughs are the lowest valleys. A wave is described by its wavelength (or the distance between two sequential crests or two sequential troughs), the wave period (or the time it takes a wave to travel the wavelength), and the wave frequency (the number of wave crests that pass by a fixed location in a given amount of time). When a wave travels, it is passing through the water, but the water barely travels, rather it moves in a circular motion.

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