The Continental Shelf

The Continental Shelf is the gently sloping undersea plain between a continent and the deep ocean. The continental shelf is an extension of the continent's landmass under the ocean. Much of the continental shelf was exposed dry land during glacial periods. During interglacial periods, like today, the shelf is submerged under relatively shallow waters. The waters of the continental shelf are rarely more than 500 feet deep, compared to the open ocean which can be miles deep. The continental shelf extends outward to the continental slope and continental rise, where the deep ocean truly begins, ultimately leading to the abyssal plain.

The figure below is a schematic diagram of the continental shelf. The width of the continental shelf around the U.S. varies considerably, from approximately 12 to 250 miles, depending on location. The U.S. Atlantic coastline generally has a wide and shallow shelf, whereas the Pacific coastline is characterized by a more narrow shelf with rapidly increasing depth. The continental shelf regions are important economically, primarily because their waters are the source of much seafood, and because of the energy these regions provide—both in the form of fossil fuels, such as oil and gas, and renewable energy resources.


The Outer Continental Shelf

The Outer Continental Shelf consists of the submerged lands, subsoil, and seabed in a specified zone up to 200 nautical miles or more from the U.S. coastline.

The Outer Continental Shelf (OCS) is regulated by the U.S. Federal government through the Outer Continental Shelf Lands Act. The OCS refers to 1.7 billion acres of Federal submerged lands, subsoil, and seabed generally beginning 3 nautical miles off the coastline (for most states) and extending for at least 200 nautical miles to the edge of the Exclusive Economic Zone, or even farther if the continental shelf extends beyond 200 nautical miles. The OCS has been divided into four regions: Atlantic Region, Gulf of Mexico Region, Pacific Region, and Alaska Region.




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