But where are deep sea (oceanic) trenches located? The majority are found around the margins of the Pacific Ocean. For this reason, the Pacific Ocean is slowly shrinking. Some examples include the Peru-Chile trench running most of the length of western South America, the Alaskan-Aleutian trench, the Cascadia trench alongside British Columbia, Washington and Oregon, the Japan trench, and others.
The deepest place indentation into the surface of the Earth is found in a deep sea trench, specifically, the Mariana Trench just to the east of the Philippines. This location is known as Challenger Deep, located at a dept of 10,911 meters (35,798 feet) below sea level.
However, there are oceanic trenches elsewhere in the world. For instance, the Puerto Rico trench, which begins on the east margin of Cuba, runs by Puerto Rico and further south along the margin between the Caribbean and Atlantic plates. In the Mediterranean, there is a small subduction zone south of Crete, represented by the Hellenic trench.