Africa’s continental crust hosts a variety of geologic terrains and is crucial for understanding the evolution of its longest-lived cratons. However, few of its seismic models are yet to incorporate the largest continent-wide noise dispersion datasets collected on the continent. Here, we report on new insights into Africa’s crustal architecture obtained using a new dataset and model assessment product, ADAMA, which comprises a large ensemble of short period surface wave dispersion measurements. We construct a continent-wide model of Africa’s Crust Evaluated with ADAMA’s Rayleigh Phase maps (ACE-ADAMA-RP). Phase and group dispersion maps are obtained with a probabilistic inverse modeling approach allowing us to provide constraints on uncertainty.  Error statistics suggest Rayleigh phase maps are better resolved and a perturbational inverse approach based on Rayleigh waves is the basis of our update of Africa’s crustal shear velocity. This model update reveals new insights into the architecture of Africa’s crust not previously imaged: (1) the fastest velocities confined to the edges of the Congo craton, the west-African cratons and the Sahara Metacraton, and (2) sharp spatial gradients along craton edges, mobile belts, and within rifted margins. While most of the reported features are robust, probabilistic modeling suggests caution in interpreting features where illumination is compromised by low-quality measurements, sparse coverage or both. Future extension of our approach to other complementary seismic and geophysical datasets - e.g, multimode earthquake dispersion, receiver functions, gravity and mineral physics, will enable continent-wide lithospheric modeling that extends resolution to the upper mantle.

West Africa continues to host a growing number of low and intermediate-magnitude earth- quakes (M2-5) along its passive margins, and its continental interior. Earthquake activity in these regions raises the need to comprehend the causes and the tectonic controls of the seismicity. Unfortunately, such studies are rare. Here, we apply single-station inversion techniques to constrain fourteen focal mechanisms, computed after compiling a set of high- quality waveforms. We describe the connection between seismicity, the contemporary stress field, anthropogenic activity, and Holocene fault scarps in the region. Our results indicate transpressive stresses acting on the inherited brittle structures in the passive margins. We also observe a compressive regime in the intracontinental failed rifts. We attribute the seismicity to the reactivation of ‘weak’ faults in the Neoproterozoic and Mesozoic failed rifts, the passive transform structures, and the intracratonic Precambrian brittle shear zones.