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Did You Know: Seafloor Gravity

We can use the Earth's gravity to map the sea floor.

Credits

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory (https://earthobservatory.nasa.gov/).
 


  • Gravity map of the ocean floor based on data from the ERS-1 and GEOSAT satellites: Scripps Institution of Oceanography, UC San Diego

  • Global Marine Gravity v.23.1, based on data from CryoSat-2 and Jason-1 satellites: Scripps Institution of Oceanography, UC San Diego, 2014 

  • Written by Margaret Carruthers

Transcript

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Text, Did you know? Gravity and the sea floor.
 
We can use Earth's gravity to map the sea floor. A picture of the Pacific Ocean, east of Australia.
 
Text, Two-thirds of Earth's surface is covered with water. We can't see the ocean floor from space because the seawater blocks our view.
 
But we can use satellite data to make gravity maps of the ocean floor. A gravity map of the ocean floor based on data from the E.R.S. 1 and GEOSAT satellites by the Scripps Institution of Oceanography, U.C. San Diego. Low gravity is dark blue near New Zealand, in grey. High gravity is orange, running parallel to it. Text, Earth's gravitational pull varies slightly from place to place. It is stronger over underwater mountains, where there is more mass. It is weaker over submarine valleys, where there is less mass. The deep blue low gravity area is labeled Valley. Text, Slight variations in gravity reveal landforms hidden deep under water. Picture of Global Marine Gravity, version 23.1, based on data from CryoSat 2 and Jason 1 satellites, by the Scripps Institution of Oceanography, U.C. San Diego, 2014. Trenches and mountains are dark blue and orange. Text, On a gravity map, we can see mid-ocean ridges, deep sea trenches, fracture zones, and lines of seamounts. Seamount at center left, mid-ocean ridge at bottom left, fracture zone at bottom center, and trench at top center. Text, Scientists can use satellite gravity data to map tectnoic plate boundaries, and to figure out how Earth's surface has changed over time.