It is estimated that only 5-15 percent of the ocean floor has been mapped through sonar technology. Since sonar can only reveal the detailed ridges and trenches beneath the sea when ships pass over a given area, only shipping routes and areas studied via special expeditions have been recorded. Yet, NASA’s Earth Observatory has shared how geodesy – or measuring Earth’s shape and gravity field – can unveil the most detailed map of the oceans’ floors to date.
David Sandwell from the Scripps Institution of Oceanography and Walter Smith from the National Oceanic and Atmospheric Administration have spent 25 years working to gain access to information about Earth’s gravity fields from the military and satellite operators. The data they collected regarding gravity measurements and sea surface heights have helped to create the most impressive map of what lies beneath the oceans’ surfaces.
Data from the European Space Agency’s CryoSat-2 and from the NASA-CNES Jason-1 mission, as well as information from decades-old missions, shed light on how underwater seamounts and other large masses have their own gravitational effects. These masses pull water toward their center of gravity and create visual “bumps” on the sea surface, which can be measured and mapped. Through these means, thousands of previously uncharted structures can now be seen on the revolutionary map at a scale of 5 kilometers per pixel.
This evolution of technology can help scientists follow the movements of Earth’s tectonic plates over time and target areas to study further using sonar scanning. The magnitude of seeing the peaks and valleys of undiscovered, deep-sea marine territories is a huge milestone in understanding our planet. The non-invasive methods also promise a future which includes a vast knowledge of our environment without causing harm to it.
Images via Earth Observatory at NASA