A deep fracture or break, about 25-50 km (15-30 miles) wide, in the earth's crust, creating an elongated valley bounded by two or more faults. a valley with very steep sides, formed by the cracking and moving of the Earth's surface. Elongated trough formed by the subsidence of a segment of the Earth's crust between dip-slip, or normal, faults. Rift valleys are usually narrow and long and have a relatively flat floor. The sides drop away steeply in steps and terraces. Rift valleys are found on the continents and along the crests of oceanic ridges. They occur where two plates that make up the Earth's surface are separating (see plate tectonics). Submarine rift valleys are usually centres of seafloor spreading, where magma wells up from the mantle. The most extensive continental rift valleys are those of the East African Rift System; other notable examples include Russia's Baikal Rift Valley and Germany's Rhine Rift Valley
1 A valley of regional extent formed by block faulting in which tensional stresses tend to pull the crust apart Synonymous with graben 2 The down-dropped block along divergent plate margins
A mosquito-borne, acute, febrile, viral disease of humans and animals, caused by an RNA virus of the genus Phlebovirus, which occurs in northern and eastern Africa
A geologic depression of southwest Asia and eastern Africa extending from the Jordan River valley to Mozambique. The region is marked by a series of faults caused by volcanic action. the Great Rift Valley a very deep, wide valley which is 3000 miles long and runs across most of East Africa and into southwest Asia. v. or Rift Valley or East African Rift System Rift system (see rift valley), extending from Jordan in the Middle East south to Mozambique in southern Africa. It is some 4,000 mi (6,400 km) long and averages 30-40 mi (48-64 km) wide. The rift has been forming for some 30 million years, as Africa and the Arabian Peninsula separate, and has produced such massifs as Kilimanjaro and Mount Kenya. The system's main branch, the Eastern Rift Valley, is occupied in the north by the Jordan River, the Dead Sea, and the Gulf of Aqaba. It continues south along the Red Sea to several lakes in Kenya. Less obvious in Tanzania, with its eastern rim eroded, it continues south to the Indian Ocean near Beira, Mozam. The western branch of the system, the Western Rift Valley, extends north from the northern end of Lake Malawi in an arc that includes lakes Rukwa, Tanganyika, Kivu, Edward, and Albert
( geology) a depression in southwestern Asia and eastern Africa; extends from the valley of the Jordan River to Mozambique; marked by geological faults