What is the name of the region where the rigid plates are moving apart?

Rigid plates are spreading centres or rift zones are where tectonic plates are moving away from each other. Often these areas are in ocean basins. The Mid-Atlantic Ridge is where the North and South American plates are moving away from the Eurasian and African plates. Magma wells up to fill the void left by the plates, forming a ridge. The Mid-Atlantic Ridge is the longest mountain chain on earth. Rift ones sometimes extend onto land. The Dead Sea/Jordan River valley is one example. Another area is in eastern Africa.