Mapping of Sediments and Crust Offshore Kenya, East Africa: A Wide Aperture Refraction / Reflection Survey Available to Purchase

In order to better understand the continent/ocean transition in the deep water Kenya, a 180 km seismic refraction line was acquired using 87 Ocean Bottom Seismographs (OBS). The Common Station Gathers were used to develop a velocity model using first break tomography, layered tomography and forward modeling. The Vp-velocity structure of the sedimentary basins and the crust was obtained and the continent/ocean transition was defined. The crustal thickness at the continental domain ranges from 18 Km at the western end of the line, thinning to 11.4 Km at its transition to the oceanic crust. Average thickness of sediments with Vp-velocities ranging from 1.8 to 4.45 Km/s, covering the stretched continental crust, is 4.8 Km. The oceanic crust is 10.8 Km thick, covered by 3.8 Km of sediments with Vp-velocities ranging from 1.8 to 3.3 Km/s. The upper part of the continental crust is laterally inhomogeneous with Vp-velocities increasing from 5.8 to 6.1 Km/s, from west to east. The oceanic crust is divided into three layers: layer 2a has Vp-velocity 4.7 Km/s, while layer 2b has Vp=5.3 Km/s, and layer 3 is fairly homogeneous with Vp-velocity 6.8 Km/s. Evaluation of PS converted phases defined a Vp/Vs ratio ~1.78 in the upper continental crust, while in the oceanic domain this ratio is ~2.00. The stretched continental crust extends eastwards for nearly 290 Km from the coast of Kenya to the oceanic domain.