How are rift valleys related to some East African plateaus?

Rift valleys and East African plateaus are closely linked through the tectonic processes that shaped the region's landscape. Many of these plateaus, such as those in Ethiopia and Kenya, were formed by the thermal expansion of the lithosphere, caused by the upwelling of hot material from the underlying asthenosphere.12

This upward bulging of the lithosphere created high-elevation plateaus, but the resulting stretching of the crust also led to the formation of the East African Rift System. In this context, the rift valleys function as deep, tectonic depressions that cut into or border these elevated surfaces. The rift floor typically lies 1,000 meters or more below the surrounding plateaus, creating steep escarpments that define the transition between the high plateau surfaces and the subsided valley floors. While some plateaus are associated with extensive volcanism triggered by these same tectonic tensions, other areas—such as the plateau holding Lake Victoria—remain relatively flat and are only intersected by minor rift features.1234