how long is rift valley
How long is the Great Rift Valley? The great rift valley is 3,700 miles long. How was the Great Rift Valley formed? It is formed by an upwelling of hot mantle material under the  valley (which has elevated the land) and then split it as the hot  mantle moves sideways away form the center â¦of upwelling. This  results in volcanoes and a Graben fault system (a rift valley)  above the upwelling.