On the Origin of Orphan Tremors and Intraplate Seismicity in Western Africa

On September 5–7, 2018, a series of tremors were reported in Nigeria’s capital city, Abuja. These events followed growing list felt the stable intraplate region, where earthquakes are not expected. Here, we review available seismological, geological, and geodetic data that may shed light on origin these tremors. First, investigate seismic records for parent location orphan using technique suitable when single-seismic station is such as Western Africa which has sparse network. We find no evidence within record Africa. Next, consider possibility local amplification from regional tectonics, reactivation basement fractures by far-field tectonic stresses, post-rift crustal relaxation, landward continuation oceanic fracture zones, or induced triggered groundwater extraction. Our assessments pose important implications understanding Africa’s seismicity its potential connection to inheritance, active anthropogenic stress perturbation.