Indroduction-Summary

Map of the location of East African Rift Valleys

The East African Rift Valley was named "The Great Rift Valley" by the explorer John Walter Gregory in the 19th century. The Great Rift Valley is an incorrect name because it pertains to seperate but related rift systems. The East African Rift is a divergent plate boundary that extends from the Afar Triple Junction southward across eastern Africa through Ethiopia, Kenya, Uganda, and Tanzania (see photo above). The boundary is in the process of splitting the African Plate into two separate plates. Geologists named the plate that makes up the majority of Africa the Nubian Plate, and the Somalian Plate is the smaller of the two that is moving away from the Nubian Plate (see photo below). The two plates together are moving away from the Arabian plate to the north, and the three meet in Ethiopia. The place where the three plates meet is called a triple-junction. Geologists today still debate why and how rifting comes about, but East Africa displays this process extremely clearly. Subterranean forces broke the earth's crust apart and large chunks of the crust sunk between parallel fault lines and forced up molten rock in volcanic eruptions. Many boiling hot springs along the rift prove that volcanic activity is extremely high along the rift system.