Deep, steep-sided depression in the ocean floor, formed when one plate of the earth's crust is pushed beneath another plate.

Narrow, deep depression in the seafloor representing the line of subduction of an oceanic lithospheric plate beneath the margin of a continental lithospheric plate; often associated with an island arc.

Also called a deep-sea trench, which is a long and narrow depression along the ocean bottom that can exceed 1 000 m in depth (maximum oceanic depths from approximately 7 300 to more than 11 000 m [24 000 to 36 000 feet]).

A long, narrow valley under the sea that contains some of the deepest points on earth.

Deep steep-sided depression in the ocean floor caused by the subduction of oceanic crust beneath either other oceanic crust or continental crust.

A linear depression of the sea floor caused by the subduction of one plate under another.

The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor.