What is a deep valley along the ocean floor known as?

A deep valley along the ocean floor is referred to as a deep-ocean trench. These trenches are among the deepest parts of the ocean and are formed by tectonic plate interactions, particularly through subduction processes where one plate is forced under another. This geological feature plays a significant role in Earth's tectonic activity and oceanographic processes.

The presence of deep-ocean trenches is critical as they contribute to phenomena such as earthquake activity and tsunamis, and they also affect ocean circulation and nutrient distribution. Understanding the characteristics and processes associated with these features is vital for comprehending the dynamics of the Earth's crust and the functioning of marine ecosystems.