Seismic Structure Beneath Africa and Arabia

The African-Arabian Rift System (AARS) has been the focus of numerous studies, but it has long been questioned whether low-velocity anomalies in the upper mantle beneath eastern Africa and western Arabia are connected, forming one large anomaly. It has also been questioned whether different tectonic provinces at the surface are connected to processes in the lower mantle (e.g., the African Large Low Velocity Province, aka the African Superplume).  Our research group has employed a variety of techniques, including adaptively parameterized tomography, double-difference tomography, receiver functions, and shear-wave splitting, to further investigated the structure beneath Africa and the Arabian Peninsula. This has generated a suite of papers that highlight our work.

(above) Tomography of the African Superplume from Hansen et al. (2012). (right) Cartoon and tomography of the mantle structure beneath Cameroon from Saeidi et al. (2023).

Africa-Focused Papers

Saeidi, H., S.E. Hansen, A.A. Nyblade, and R. Haag, Mantle Structure beneath the Damara Belt in south-central Africa imaged using Adaptively Parameterized P-wave Tomography, J. Geophys. Res. Solid Earth, 129, doi: 10.1029/2023JB027965, 2024.  Saeidi_etal_JGR_2024.pdf

Saeidi, H., S.E. Hansen, and A.A. Nyblade, Deep Mantle Influence on the Cameroon Volcanic Line, Geochem. Geophys. Geosyst., 24, doi: 10.1029/2022GC010621, 2023.  Saeidi_etal_G-cubed_2023.pdf

Hansen, S.E. and A.A. Nyblade, The Deep Seismic Structure of the Ethiopia/Afar Hotspot and the African Superplume, Geol. J. Int., 194, 118-124, doi: 10.1093/gji/ggt116, 2013.  Hansen_Nyblade_GJI_2013.pdf

Hansen, S.E., A.A. Nyblade, and M.H. Benoit, Mantle structure beneath Africa and Arabia from adaptively parameterized P-wave tomography: Implications for the origin of Cenozoic Afro-Arabian tectonism, Earth Planet. Sci. Lett., 319-320, 23-34, doi: 10.1016/j.epsl.2011.12.023, 2012.  Hansen_etal_EPSL_2012.pdf

Hansen, S.E., A.A. Nyblade, and J. Julià, Estimates of Crustal and Lithospheric Thickness in Sub-Saharan Africa from S-wave Receiver Functions, S. African J. Geol., 112, 89-100, doi: 10.2113/gssajg.112.3-4.229, 2009c.  Hansen_etal_SAJG_2009.pdf

Hansen, S.E., A.A. Nyblade, J. Julià, P.H.G.M. Dirks, and R. J. Durrheim, Upper Mantle low-velocity zone structure beneath the Kaapvaal Craton from S-wave receiver functions, Geophys. J. Int., 178, 1021-1027, doi: 10.1111/j.1365-246X.2009.04178.x, 2009a.  Hansen_etal_GJI_2009.pdf

Topography, gravity signature, and lithospheric structure from the Red Sea and across the Arabian Peninsula. From Hansen et al. (2007).

Arabia-Focused Papers

Hansen, S.E., J.B. Gaherty, S.Y. Schwartz, A.J. Rodgers, and A.M.S. Al-Amri, Seismic velocity structure and depth-dependence of anisotropy in the Red Sea and Arabian Shield from surface wave analysis, J. Geophys. Res. Solid Earth, 113, B10307, doi: 10.1029/2007JB005335, 2008.  Hansen_etal_JGR_2008.pdf

Hansen, S.E., H.R. DeShon, M.M. Driskell, and A.M.S. Al-Amri, Investigating the P-wave Velocity Structure beneath Harrat Lunayyir, northwestern Saudi Arabia, using Double-Difference Tomography and Earthquakes from the 2009 Seismic Swarm, J. Geophys. Res. Solid Earth, 118, 4814-4826, doi: 10.1002/jgrb.50286, 2013.  Hansen_etal_JGR_2013.pdf

Hansen, S.E., A.J. Rodgers, S.Y. Schwartz, and A. Al-Amri, Imaging Ruptured Lithosphere beneath the Red Sea and Arabian Peninsula, Earth Planet. Sci. Lett., 259, 256-265, doi: 10.1016/j.epsl.2007.04.035, 2007.  Hansen_etal_EPSL_2007.pdf

Hansen, S.E., S.Y. Schwartz, A. Al-Amri, and A.J. Rodgers, Combined Plate Motion and Density Driven Flow in the Asthenosphere beneath Saudi Arabia: Evidence from Shear-wave Splitting and Seismic Anisotropy, Geology, 34, 869-872, doi: 10.1130/G22713.1, 2006b.  Hansen_etal_Geology_2006.pdf