Northwest Atlantic Mid-Ocean Channel

Most topography data on the NAMOC originate from wide-range sonar scans. With a total length of about 3,800 km (2,361 mi), NAMOC is one of the longest underwater channels in the world. It is 100–200 m deep and 2–5 km wide at the channel floor. The rising levees of the NAMOC (about 100 m above the sea bed) often hinder confluence of some tributaries, which instead run along NAMOC for hundreds of km. Its western (right-hand, max. height 250 m) levee rises some 100 m above the eastern one (max. height 150 m). This asymmetry is attributed to the Coriolis effect affecting the turbidity currents, which reach velocities of 6–8.5 m/s and deposit silt and clay over the channel. The levee is absent in some parts of the NAMOC, for example between 56°N and 57°N, due to the local side-flows of sand.

The meandering of the NAMOC is relatively small compared to other underwater channels, such as Amazon Canyon. It is more developed in the northern part, with a period increasing from 25 km between 59°45'N and 56°N to 50 km between 56°N and 54°30'N. The channel becomes on average more straight towards the south, but it still contains abrupt turns due to local seamounts sea bed fractures.