Oceanic crust is constantly being pushed horizontally away from the ridge crest toward an oceanic trench. This ridge crest is known as spreading axis or spreading center. The phenomenon itself is known as seafloor spreading. Seafloor spreading as a theory was first proposed by Harry Hess in 1962. He proposed that sea floor moves, as well as continents. The seafloor moves at a rate of about 1-24 cm per year.
