T024-0020
Surface wave tomography of Southern Africa using ambient noise analysis

Thursday, 10 December 2020
Poster
Islam Fadel1, Hanneke Paulssen2, Mark van der Meijde3, Andrew Nyblade4, Raymond J Durrheim5, Austin White-Gaynor4, Andriamiranto Raveloson5, Tarzan Kwadiba6, Onkgopotse Ntibinyane7, Nortin Titus8 and Mako Sitali8, (1)University of Twente, Earth System Analysis, Enschede, 7500, Netherlands, (2)Utrecht University, Dept. of Earth Sciences, Utrecht, Netherlands, (3)University of Twente, Earth System Analysis, Enschede, Netherlands, (4)Pennsylvania State University Main Campus, Department of Geosciences, University Park, PA, United States, (5)University of the Witwatersrand, School of Geosciences, Johannesburg, South Africa, (6)Principal Geophysicist 1 & Head of Geophysics Division, Botswana Geoscience Institute, Lobatse, Botswana, (7)Botswana Geoscience Institute, Lobatse, Botswana, (8)Geological Survey of Namibia, Windhoek, Namibia
Abstract:
Recent developments in Southern Africa have contributed to the development of several temporary seismological arrays in many countries, namely, Botswana, Malawi, Mozambique, Namibia, South Africa, Tanzania, Zambia, and Zimbabwe. These developments have led to seismic records from more than 300 stations between 1990 and now. The temporary arrays have significantly contributed to the understanding of the crustal and upper mantle structure of Southern Africa. However, the incoherent methods and approaches used have led to many conflicting interpretations and results, especially about the nature and influence of the East African Rift System on the southern Africa crustal structure and uppermost mantle.

In this research, we use data from more than 300 stations throughout the southern African region to derive fundamental mode Rayleigh wave group and phase velocity maps between 3-35 seconds. The group and phase velocity maps were then used to establish the shear wave velocity of the crust and uppermost mantle. The model shows interesting features, including the sedimentary basins, the cratonic blocks, and the mobile belts. Moreover, the model gives an interesting insight into the East African Rift System extension in the crustal and uppermost mantle of the region.
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