RELEVANCE OF AFAR SEISMICITY AND VOLCANISM TO THE MECHANICS OF ACCRETING PLATE BOUNDARIES

The seismicity, the horizontal and vertical ground displacements, and the geometry of active faults and fissures during the seismic and volcanic events of November 1978 in Southern Afar are consistent with an accentuation of the pre-existing topography of the Ghoubbet-Asal rift. The zone of sizeable permanent deformation is restricted to several hundred square kilometres. Elastic rebound models seem to explain the observations. The events occurred in the vicinity of the suggested location of the tip of a lithospheric crack which may have been responsible for the progressive opening of the western Gulf of Aden. © 1979 Nature Publishing Group.