Where do sea trenches form?

Sea trenches form at convergent plate boundaries where one tectonic plate is subducted beneath another. This typically occurs in regions where an oceanic plate collides with a continental plate or another oceanic plate. As the denser oceanic plate sinks into the mantle, it creates a deep, narrow depression in the ocean floor, resulting in a trench. The Mariana Trench is the most well-known example of this geological feature.