Abyssal Hill

An abyssal hill is a small, elongate elevation on the abyssal seafloor, typically 50 to 300 m high and a few kilometers wide, formed at a mid-ocean ridge and carried outward by seafloor spreading. The hills run parallel to the ridge axis, built by faulting and volcanism as new crust cools and stretches near the spreading center. They are the most abundant landform on Earth, covering much of the deep ocean floor between the ridge crest and the sediment-blanketed abyssal plain. Hill spacing and relief scale with spreading rate: slow ridges make taller, rougher hills than fast ones.