Seismogenic Fault Reactivation in Western Central Africa: Insights From Regional Stress Analysis

The onshore continental margins of western Central Africa have been hosting potentially damaging earthquake events for decades; yet, the links between seismicity, contemporary stress field, and pre-existing faults are not well understood. Here, we analyze regional fields offshore along coastal margin, in interior areas using focal mechanisms, map characterize detailed structure preexisting fault systems outcrops, assess their reactivation potential. Our results show a switch from NNE-SSW transpressive regime near margins, to NE-SW compressive transtensive regimes cratonic (Congo Basin Kasai Block). We that stresses acting on oceanic fracture zones compatible with those margin. Field observations reveal presence large deform both Precambrian basement Phanerozoic sedimentary sequences, widespread calcite veining, quartz palygorskite mineralization (with evidence post-veining shear reactivation) zones. Along NNE-, NNW-, N-S -trending strike-slip normal high slip tendency (>80%–100%), whereas interior, NW- thrust most likely reactivate. argue favorable orientation define susceptibility seismic reactivation. propose higher magnitudes distal extend further into continent may be driving loading pre-stressed, favorably oriented onshore,