Wave processes and shoreline change

Article By:

Ashton, Andrew Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts.

Murray, Brad Department of Earth and Ocean Sciences, Duke University, Durham, North Carolina.

Last reviewed:2010

DOI:https://doi.org/10.1036/1097-8542.YB100209

Shorelines are among the most strikingly dynamic geological features on the planet. Winds, waves, and tides are constantly reshaping the coast, moving the shoreline back and forth. Where waves have caused significant deposition along the coast, the shore consists primarily of sand and gravel. Of social, financial, and often sentimental value, the sandy coasts of the world increasingly are being developed despite the ongoing changes that endanger structures and infrastructure built near the shore. Increased rates of sea-level rise over the last century already threaten many developed coasts; these risks will only increase over the coming decades and centuries with predicted increases in the rate of sea-level rise. Coastal scientists endeavor to understand how coasts change. Predicting future coastal changes requires an understanding of how and why coasts have both eroded and accumulated over time. Although beaches and sandy coastlines, such as barrier islands, are currently mostly being eroded or are moving landward, these shores were originally formed through depositional processes. Coastal landforms can store information about the environmental conditions in the past and can help us better understand how the world's coasts could behave in the future. Until recently, the cause of several types of coastline shapes—regularly spaced coastal undulations and landforms—has been poorly understood.

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