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Image depicting satellite captured, bathymetric data of the western Atlantic Ocean Basin and its ocean floor features. Credit: NOAA's National Environmental Satellite and Information Service.
The ocean surface is bumpy. Big mounds of water can rise up to hundreds of feet high. No one notices them because they’re many miles wide, so their slopes are gentle. They are detected, though, by orbiting satellites. And scientists can use the satellite measurements to learn about what’s far below the bumps — on the ocean floor.
In late 2014, in fact, researchers published the most detailed map of the ocean floor yet produced — compiled mainly from six years of observations by two satellites. The satellites use laser altimeters to measure the height of the ocean surface. Features on the ocean floor exert a gravitational pull on the water above them, causing changes in the surface. A volcanic mountain, for example, is made of dense rock, so it pulls more water toward it — creating one of those “bumps” on the surface.
The scientists used sophisticated computer processing to convert the measurements of surface elevation into a map of the ocean floor. It’s the most complete and detailed map to date, offering new views of the 80 percent of the ocean floor that hasn’t been charted by ships.
The map reveals thousands of previously unseen mountains known as seamounts. It also found evidence of a region in the Gulf of Mexico where new crust was formed 150 million years ago, plus a younger volcanic ridge off the coast of Africa. The map will help geologists better understand the slow drift of the plates that make up Earth’s crust — and give all of us a rare view of the bottom of the sea.
