American Oceanographic Expedition using echolocation found at the bottom of the deepest in the world Mariana Trench, located in the Pacific Ocean, four range up to 2.5 kilometers, according to a statement on the website of the University of New Hampshire (USA).
Scientists have created the first accurate map of the three-dimensional terrain model and the bottom of Mariana Trench. From August to October 2010 expedition spent filming bottom area of about 400,000 square kilometers with a multibeam sonar, has a resolution of 100 meters.
Analysis of satellite imagery allows scientists to suggest before the existence of the hills at the bottom of the Mariana Trench, but detailed studies on the site led to the geographical discovery: the deepest depression in the land crossed by at least four oceanic ridges.
"At this point in the geological structure of the oceanic crust is very difficult … These ridges were formed about 180 million years ago in the constant movement of tectonic plates. Marginal part of the Pacific plate over millions of years, gradually "creeping" under Philippine, as an older and "heavy" … In the process, form fold (more dense rocks "resisting" force, tighten them under the edge of the Philippine plate and form a "crease" , surging as mountains near plate boundaries — Ed.) "- said Gardner.
According to the assumptions of experts from the Hydrographic Center at the National Oceanic and Atmospheric Administration (NOAA) United States, the formation of these ridges is no "peace" — it could be due to the large underwater earthquakes like the one in March 2011 triggered a devastating tsunami in Japan, with disastrous consequences.
The expedition also specify the parameters of the deepest point of the Mariana Trench and the Earth — "Challenger Abyss." New Dimensions "deepened" it on 23 meters (10.994 vs. 10.971 kilometers on 2009 data). However, the scientists point out that it is possible to guarantee the accuracy of up to 40 meters. "For measurements at a depth of 11 kilometers have to put up with the inevitable inaccuracy of measurement," — said the research, NOAA employee and the University of New Hampshire, James Gardner.
Since 1875, when measurements from aboard a British corvette "Challenger" showed the depth of 8.184 kilometers, the data repeatedly specified. Maximum depth ever measured from a Soviet research vessel "Vityaz", but later it turned out that scientists in taking the readings have not considered changing environmental conditions at different depths. This wrong mark — 11.023 kilometers — is still present in many physical and geographical maps of the Soviet and Russian production. The complexity of the measurements is that at different depths are very different temperature and pressure (bottom cavity above atmospheric more than 1100 times), and it requires a complex conversion readings.
At the bottom of the Mariana Trench humanity "penetrated" only three times. The only person dive to the bottom of the Mariana Trench was committed January 23, 1960 U.S. Navy Lieutenant Don Walsh and Jacques Picard researcher at bathyscaphe Trieste. They had been at the very bottom cavity 20 minutes and found a life — flat fish, similar to flounder, measuring up to 30 centimeters. At the maximum point of immersion devices a record depth of 11.521 kilometers, after correction "Socrates" by more than half a kilometer. In 1998 and 2009, fell to the bottom of basin automatic underwater vehicles — Japanese probe Kaiko and then an American submarine catamaran Nereus, who first made the photo and video, selected geological and biological samples, and captured several inhabitants record depths.