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.
Islands and inlets grow and disappear within 30 years along the shores of Cape Cod.
USGS-NASA Landsat satellites captured these images of the Nauset-Monomoy barrier beach system between June 1984 and July 2013.
The first major change appeared in 1987, when a storm cut a new inlet through North Beach, forming what the locals called South Beach Island.
In 2007, a storm cut a new inlet through North Beach, creating North Beach Island. South Beach also became connected to South Monomoy.
A 2013 nor'easter cut a new inlet across South Beach, severing the connection to Monomoy.
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Credits
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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Writer
- Mike Carlowicz (Sigma Space Corporation)
Release date
This page was originally published on Thursday, July 17, 2014.
This page was last updated on Wednesday, May 3, 2023 at 1:50 PM EDT.