WHY IS THE MARIANA TRENCH SO DEEP?

The Beginning 

    Did you know that the Mariana Trench has a deep part called Challenger Deep? The name comes from the British ship that discovered it in 1872.

Where is it?

     The Mariana Islands are a part of a chain of islands in the Pacific Ocean. The Mariana Trench was discovered in 1875 during a Challenger Expedition. The Mariana Trench is a U.S. Territory, which means that those lands are owned and controlled by the United States.

     The Challenger Deep is the deepest spot in the Mariana Trench located in the south west of Guam. The Mariana Trench is located on the western side of the north Pacific Ocean. 

How it was made 

The Mariana Trench formed when two tectonic plates collided. One plate forced itself under the other plate, pushing the older oceanic crust into the mantle. The mantle is a rocky inside layer of Earth below the Earth's crust. The crust is the outside layer of the Earth.

Deep & Wide

      The Mariana Trench has the deepest area on earth. In 1899, scientists discovered an even deeper area than they found during the 1875 Challenger expedition. The deeper area was southeast of Guam and was known as the Nero Deep. The depth of Nero Deep was 31,693 feet (9,660 meters). 

     A new world record depth of 36,056 feet was found in 1957 in Challenger Deep by a Soviet ship.  

     The Mariana Trench is not only deep, it is also long and wide. The Mariana trench stretches in length more than 1,580 miles (2,540 kilometers). The width is 43 miles. The Mariana Trench is the deepest known trench on the earth. The location is southeast of the Mariana Islands. The Mariana Trench is deeper than Mount Everest's height. 

Water Vehicles

    Scientists from the Challenger Expedition used a lead weight to find the depth. This was their first attempt to measure the depth of the Mariana Trench. In the 1950s, a submarine type vehicle was created by Auguste and Jaqanes Piccard for ocean exploration in deep water. Over the years the equipment used for the measurements is newer and more high-tech. The Challenger measured the sounding as 26,850 feet or 8,184 meters at the southern region of the trench. A Japanese expedition in 1984 reached a depth of 35,840 feet. In 2010, a U.S. research team recorded a depth of 36,071 feet.

     Currently, the deepest measured part of the Mariana Trench is 36,201 feet deep (11,034 meters), which is about seven miles deep.

Sirena Deep

     In 1997, a team of scientists from Hawaii found another deep location in the Mariana Trench which was originally called HMRG Deep. The line hit the bottom of the trench so they can see what the depth is. The depth of HMRG Deep measured 35,151 feet. Sounding is the name of the process they used. 

    The group changed the name to Sirena Deep. The name Sirena comes from a folktale in Guam about a young girl who turned into half-fish because she was a bad girl who didn't follow the rules.

     During the trip to survey Sirena Deep, the ship scraped sand from the ocean floor and found the life form called radiolaria living at the bottom of the Mariana Trench. Radiolaria is a form of zooplankton, a tiny organism that floats in the sea.