Interpretation of Tensor Gravity Data Using an Adaptive Tilt Angle Technique

The Lotikipi Basin is a rift basin lying within the East African Rift System, west of Lake Turkana in north west Kenya. The basin is filled with a 4km sequence of volcanic derived sediment, stacked rhyolite flows and olivine basalts, underlain by supposed reservoir potential sediments at least 500m thick. 2D Seismic imaging is observed to be degraded below the shallow volcanic sequences. Basalts are strongly absorbent of p-wave energy, so act as high impedance barriers to the seismic energy. Seismic reflectors below the basalt are therefore poorly defined. Consideration is given to gravity processing and quality control methods that can be used to review data when its description is incomplete. Other data sources and previous gravity interpretation can be employed to define a gravity model that fits the seismic interpretation and other qualitative information. Gravity modelling enables better constraint on the interpretation through thick intrusive shadow zones (using known seismic facies) and provides better estimation of the thickness of the basin’s deep sediment, as well as basinal depth to Precambrian basement.