9316868 Keller The results of Kenya Rift International Seismic Project (KRISP) experiments in 1985 and 1989 90 provide an excellent and unexpected picture of lithospheric structure in the central and northern portion of the Kenya rift. From the apex of the Kenya dome (near Lake Naivasha, northward) the crust thins, the physiographic expression of the rift widens, the floor of the rift valley and the rift shoulders lose elevation, and the amount of extension increases. Two interfaces within the mantle also deepen to the north. The lithospheric mantle is thinned considerably more than the crust indicating that an active process is at work. These observations lead to the obvious question of what happens in the southern portion of the rift. The southern portion of the Kenya rift is the focus of this research. In this project, the U.S. team of researchers will join with the University of Karlsruhe, The University of Leicester, the Dublin Institutes for Advanced Studies, the University of Potsdam, and Kenyan colleagues to conduct a variety of geophysical and petrological studies in southern Kenya. The primary emphasis of these studies will be determining lithospheric structure and formulating an integrated model of the evolution of the rift. The University of Karlsruhe will concentrate on the eastern flank of the rift and tie their results to recent petrologic results. The University of Leicester and the University of Texas at El Paso will concentrate on a long profile crossing the rift just north of the Tanzanian border. By using shotpoints in Lake Victoria and the Indian Ocean, this 700km long profile provides a unique opportunity to probe the deep struct ure of an active plume. The University of Texas at El Paso will also concentrate on the operation of a small seismic array including broadband recording, gravity studies, petrological studies, and the integrated analysis of the combined results. ***
