A SURFACE WAVE DISPERSION STUDY OF THE LITHOSPHERIC STRUCTURE OF AFRICA
Lithospheric structure of the African continent is, in general, poorly known; the analysis of surface wave dispersion provides the only remaining opportunity to add to our knowledge of African lithospheric structure using existing data sets. In this study, long-period, vertical-component seismograms were analyzed from WWSSN seismograph stations in the region. Two-station analysis was undertaken for all paths that could provide new information. A new set of computer programs including phase match filtering and inversion were implemented for this study.^ The results of this study indicate that the crustal thickness in almost all of Africa is 40 km $\pm$ 5 km. Thin ($<$30) crust is found in the area of the East African rift and an area of thickened crust is found in northern Africa. Areas underlain by a well-developed upper mantle low velocity layer are limited to the East African rift and north Africa. This result would suggest that the lithosphere may be quite thick ($>$150 km) under much of Africa. Very low phase velocities (and lithospheric shear wave velocities) are found in the East Africa rift area. The high phase velocities associated with the shield areas of southern Africa are not characteristic of the remainder of the continent. The areas of Tertiary uplift and volcanism in northern Africa seem to correlate with a thickened crust but thinned lithosphere. ^
YOUSEF, ALI ABDULAH, "A SURFACE WAVE DISPERSION STUDY OF THE LITHOSPHERIC STRUCTURE OF AFRICA" (1987). ETD Collection for University of Texas, El Paso. AAI8721372.