Science glossary film: Trench

An oceanic trench is a deep, narrow depression in the ocean floor along a subduction boundary where one tectonic plate is pushed under the other. They are long, often run parallel to volcanic island arcs, and are very deep. The deepest known parts of the ocean are all trenches, including the 11,000-metre Challenger Deep in the Mariana Trench.

They are long, often run parallel to volcanic island arcs, and are very deep. The deepest known parts of the ocean are all trenches, including the 11,000-metre Challenger Deep in the Mariana Trench.