The Western Africa model (v2018.0.0) was developed internally by GEM. The model encompasses the whole Atlantic side of the Africa continent. An ad-hoc homogenised earthquake catalogue was developed based on globally available information, which was used as the primary base for seismic occurrence analysis and the subsequent development of the source zonation model.

The analysis was particularly challenging in the region, due to the severe incompleteness of calibration data, and the virtually nonexistent neotectonic information. Since the original version, an update was made to the model by the GEM hazard team, leading to the latest release (v2018.1.0), which was used in the computation of the 2023 Global Earthquake Hazard and Risk Maps.

This model extends the minimum magnitude of events for crustal distributed seismicity and includes an additional GMPE in the logic tree.