Adaptively Parameterized P- and S-wave Tomography in Africa: Assessing Deep Mantle Influence on Surface Geology

Various seismic investigations in Africa have tried to assess the potential connection between surface geology and the African Large Low Velocity Provinces (LLVP); however, numerous questions still exist regarding how lower mantle processes influence those seen at the surface. Using adaptively parameterized teleseismic travel-time tomography, we are expanding such studies, particularly to improve imaging at mid- to lower mantle depths, which are critical to assess mantle dynamics. Data from the International Seismological Center catalog as well as from temporary deployments throughout Africa have been combined, leading to the largest collection of travel-time residuals recorded across the continent to date. These data have been used to develop new P- and S-wave velocity (VP and VS) models that provide strong evidence for connections between the LLVP and features in both western and eastern Africa, including the Cameroon Volcanic Line and the East African Rift System. Further, results from both models are being combined to develop self-consistent VP /VS estimates, which will allow us to assess the thermal versus chemical structure of the LLVP. Ultimately, our work will further elucidate how surface features in Africa depend on deep mantle influence.