Broadband Seismic Investigation of Crust and Upper Mantle Structure Beneath Kenya

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Abstract for proposal EAR0003424 (PH #45x)Title: Broadband Seismic Investigation of Crust and Upper Mantle Structure Beneath KenyaPI: A. Nyblade, Penn StateIn this project, we will critically evaluate models for the origin of rifting, volcanism and uplift in East Africa by imaging the seismic structure of the upper mantle beneath the Kenya rift using broadband seismic data. Although East Africa has long been regarded as a classic area in which to study the early stages of continental breakup, the origin of the Cenozoic rifting, volcanism, and plateau uplift found there is still poorly understood. For a variety of reasons, the rifting, volcanism, and plateau uplift has been commonly attributed to one or more mantle plumes. However, whether a plume exists beneath East Africa is a contentious issue because geochemical and geophysical data from there, until recently, have provided little information on mantle composition and thermal structure beneath the lithosphere where the plume is hypothesized to lie. To further test plume models for East Africa, as well as non-plume models, we will conduct a passive source seismic experiment in Kenya to obtain broadband seismic data. The data will be analyzed using a number of proven modeling techniques for imaging crust and upper mantle structure. The resulting seismic images, combined with geochemical and other geophysical data from East Africa, will let us identify thermal and/or compositional structures in the upper mantle that can, in turn, be used to discriminate between models of the structure and development of East Africa.