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How do gravity maps reveal ridges, fracture zones, and other features of the ocean floor?

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Gravity maps reveal seafloor features by measuring subtle variations in the shape of the ocean surface, which acts as a sensitive indicator of marine topography.1

This process relies on satellite technology, specifically radar altimeters, which measure the distance between a satellite and the sea surface with high precision. Because massive seafloor features exert a gravitational pull, they cause the ocean surface to warp:12
* Seamounts: These dense, elevated features create gravitational attraction that causes the ocean surface to bulge upward over them.1
* Deep-sea trenches: These areas cause the ocean surface to downwarp due to lower gravitational attraction.1

By calculating the gravity field from these surface measurements, researchers can create comprehensive gravity maps that depict previously uncharted features, including ridges and fracture zones. This method provides a more complete, synoptic view of the ocean floor than is possible with ship-based echo soundings, allowing scientists to identify linear patterns of gravity anomalies that reveal the underlying geologic structure of the ocean basins.1