What is a Trench?
At least 22 trenches have been identified although not all are classified as major.
Of this number, 18 are in the Pacific Ocean, three in the Atlantic Ocean, and one in the Indian Ocean.
Where, and What is the Mariana Trench?
The Mariana Trench is located in the Pacific Ocean, just east of the 14 Mariana Islands (11"21' North latitude and 142" 12' East longitude ) near Japan. As you probably already know, it is the deepest part of the earth's oceans, and the deepest location of the earth itself. It was created by ocean-to-ocean subduction, a phenomena in which a plate topped by oceanic crust is subducted beneath another plate topped by oceanic crust.
But just how deep is the Mariana Trench?
First off, here are the average depths of the earth's oceans; the Arctic Ocean is 1,038 meters (3,407 feet) deep, the Indian Ocean is 3,872 meters (12,740 feet) deep, the Atlantic Ocean is 3,872 meters (12,254 feet) deep and the Pacific Ocean is 4,188 meters (13,740 feet) deep.
The deepest point in each of the earth's oceans are as follows; the Arctic Ocean's Eurasian Basin at 5,450 meters (17,881 feet) deep, the Indian Ocean's Java Trench at 7,725 meters (25,344 feet) deep, the Atlantic Ocean's Puerto Rico Trench at 8,648 meters (28,374 feet) deep and the Pacific Ocean's Mariana Trench at 11,033 meters (36,201 feet) deep.
The deepest point of the Mariana Trench is called The Challenger Deep , so named after the British exploration vessel HMS Challenger II, and it is located 210 miles south-west of Guam. This depth was reached in 1960 by the Trieste, a manned submersible owned by the U.S. Navy.
In order to better illustrate the actual depth of the Mariana Trench, consider the following; if Mount Everest, which is the tallest point on earth at 8,850 meters (29,035 feet), were set in the Mariana Trench, there would still be 2,183 meters (7,166 feet) of water left above it.
The Mariana Trench is often used as a North-South passage by submarines as it is part of a long system of trenches that circle the Pacific Ocean, connected with the Japan and Kuril Trenches.