East African earthquake body wave inversion with implications for continental structure and deformation

Abstract

Source parameters for five African intraplate events are obtained from body wave inversion for the moment tensor. Parameters for the events are as follows: (Table presented) The Ethiopia and Zaire events exhibit normal faulting as would be expected for their rift zone locations. The 1968 May 15 Zambia event is unusual in that P‐pP separation times place its focus in the lower crust (28 km) which may be below the brittle/ductile transition zone implying high strain rates. Inversion yielded a high angle normal fault. The depth and focal mechanism of this event, along with the mechanism for the 1968 December 2 Zambia event, suggest southwestward rift extension. Teleseismic long period vertical P‐waves from the South Africa event exhibit distortions that may be attributed to lateral inhomogeneities in the source structure. Copyright © 1988, Wiley Blackwell. All rights reserved