Earth  ID: 11587

The Moving Shoreline

Beaches are dynamic, living landscapes, and the prime example of their evolution is the coastal barrier. These islands and spits run parallel to the mainland and protect it from the full force of ocean winds and waves. More than 2,100 barriers front about 10 percent of the world’s continental shorelines. These sandy barriers are constantly raised up, shifted, and torn down by the natural ebb and flow of waves, currents, winds, and tides. Hooks form, inlets open and close, and beaches slowly march across their back bays and lagoons toward the mainland. This process allows them to naturally move ever upwards as sea levels rise. Since 1984, USGS-NASA Landsat satellites have observed coastline changes off of Chatham, Massachusetts, on the southeastern elbow of Cape Cod. Over the past 30 years, three major breaches opened, and barrier islands connected to the coastline and to each other. Watch the video to see the changes unfold.

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NASA Earth Observatory

Story Credits

Lead Writer:
Mike Carlowicz (Sigma Space Corporation)

Please give credit for this item to:
NASA's Earth Observatory
Cover image courtesy of ©2014 Spencer Kennard, Kelsey-Kennard Photo-Gallery
Satellite images courtesy of NASA Earth Observatory/Jesse Allen and Robert Simmon

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