Mariana Trench was located in the western Pacific Ocean,at the east of Mariana oceans this trench was estimated 35,994 feet deep and about2,550 kilometres long but has a width of only 69 kilometres.
Before that Mariana Trench were claimed by Spain in 1667,Spain established a colony there, and gave the islands the official title of Las Marianas in honor of Spanish Queen Mariana of Austria, widow of Philip IV of Spain.Thus the name of the trench derived from this. The islands are part of the island arc that is formed on the over-riding plate, the Philippine plate, on the western side of the trench. The Pacific plate is being subducted under the islands, forming the trench.
Below was the the graphic of Mariana Trench