The 2009–2010 Ouazzane seismic sequence: evidence for a possible active horsetail-like termination of the Jebha Fault, Rif belt, Northern Morocco

The western-central Rif is characterized by diffuse seismicity, including a pronounced earthquake sequence occurring in 2009–2010 near Ouazzane, southwest of the Jebha Fault. The structural significance of this sequence and its relationship to the regional fault system remain poorly constrained. We analyzed the regional earthquake catalogue, performed double-difference hypocentral relocation and GardnerKnopoff declustering, and integrated regional focal mechanisms with mapped geological structures to investigate the spatial organization and seismotectonic significance of the Ouazzane sequence. Relocated hypocentres are concentrated mainly within the upper 30 km of the crust and define several spatially separated and oblique clusters rather than a single continuous fault plane. The persistence of the principal Ouazzane concentration after declustering indicates that the observed pattern is not produced solely by conventional mainshockaftershock sequences. Regional focal mechanisms are dominated by strike-slip faulting but also include normal and reverse components, indicating kinematic partitioning among structures of different orientations. These observations are consistent with a structural model in which deformation associated with the southwestern terminal zone of the Jebha Fault may be transferred into a distributed system of concealed subsidiary structures within the External Rif nappe stack. The inferred branches are conceptual structures constrained by hypocentral distributions and regional fault architecture rather than directly mapped active fault surfaces. We therefore interpret the 2009–2010 Ouazzane sequence as consistent with a possible active horsetail-like termination near the southwestern end of the Jebha system, without demonstrating a continuous active fault connection between Jebha and Ouazzane. This potentially underrecognized seismogenic zone has implications for understanding active deformation and seismic hazard in the western External Rif.