The East African Rift or East African Rift System is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. In the past it was considered to be part of a larger Great Rift Valley that extended north to Asia Minor.
A narrow zone, the rift is a developing divergent tectonic plate boundary where the African Plate is in the process of splitting into two tectonic plates, called the Somali Plate and the Nubian Plate, at a rate of 6–7 mm per year. The rift system consists of three microplates, the Victoria Microplate to the north, and the Rovuma and Lwandle microplates to the south. The Victoria Microplate is rotating counter-clockwise with respect to the African plate. Its rotation is caused by the configuration of mechanically weaker and stronger lithospheric regions in the EARS.
As extension continues, lithospheric rupture will occur within 10 million years; the Somali Plate will break off and a new ocean basin will form.