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deep-sea trench Explained

deep-sea trench at English => English (The Britannica Concise) Of Explained:

Any long, narrow, steep-sided depression in the ocean bottom in which maximum oceanic depths (24,000-36,000 ft, or 7,000-11,000 m) occur. The deepest known depression of this kind is the Mariana Trench. Most trenches occur at subduction zones, where one tectonic plate is thrust under another.