The East African Rift is a vast system of normal faults stretching thousands of kilometres from the Afar region in the north through Ethiopia, Kenya and Tanzania toward Mozambique. It is not a single fault but a divergent boundary where the African continent is slowly splitting into the Nubian and Somali plates.
The dominant motion is extensional: the crust is being stretched and thinned, dropping down along normal faults to form the deep valley floors, escarpments and lakes such as Tanganyika and Malawi. Rifting proceeds at only a few millimetres per year, accompanied by widespread volcanism from Kilimanjaro to the Ethiopian highlands.
Earthquakes along the rift are frequent but generally moderate, reflecting the shallow, extensional style of faulting rather than the giant ruptures of subduction zones. Over millions of years this rifting is expected to open a new ocean, eventually detaching the Horn of Africa from the rest of the continent.