It is the deepest trench in the world’s deepest ocean, and now scientists have a new map of it. Using sound waves, scientists have pierced the lightless depths of the western Pacific Ocean and drawn a new picture of the Mariana Trench.
James Cameron made news in March 2012 as the first person to dive to the Challenger Deep in a submersible in more than 50 years. Don Walsh and Jacques Piccard made the first dive in 1960 in the U.S. Navy bathyscaphe Trieste.
The maps above were made from data collected and analyzed by researchers at the Center for Coastal and Ocean Mapping/Joint Hydrographic Center at the University of New Hampshire (UNH). Depths are reflected by shades of blue, with the deepest reaches represented by the darkest blues. The black outline shows the outer edges of the nearly 400,000 square kilometers of seafloor surveyed by the oceanographers.
The researchers used multi-beam echo sounders to map the Mariana Trench from August to October 2010. Mounted on the hulls of ships, the instruments send pulsed sound waves toward the seafloor and then record the echo-like reflections. Multi-beam sounders send those pulses out in a fan-shaped swath, allowing researchers to form three-dimensional images of the bottom.
Led by UNH scientists James Gardner and Andrew Armstrong, the underwater survey has yielded the most precise estimate to date of the depth of the Challenger Deep—10,994 meters deep (36,069 feet), plus or minus 40 meters. Researchers also discovered four deep-water “bridges” crossing the trench and standing as much as 2,500 meters above the trench floor. The new map has a resolution of 100 meters per pixel, nearly 20 times more detailed and precise than previous efforts (two kilometers per pixel).