Membrane tectonics and the East African Rift

Abstract

It is proposed that the East African Rift System is a propagating fracture system caused by membrane stresses in the lithosphere. The membrane stresses are due to the northward movement of the African plate on a non-spherical earth. The theory predicts that the interior of the African plate should be in tension and that the membrane stresses within it should be sufficient to fracture the lithosphere. The location of the rift system within the plate and the magnitude of the crustal extension observed along the rift are both consistent with such a hypothesis. The southward migration of the onset of rift volcanism with time is expected as the continent continues to change latitude and the tension fracture propagates southward. Once initiated volcanism along such fracture continues as long as the lithosphere stays in tension.