Akademik Veri Yönetim Sistemi
Tectonophysics, cilt.929, 2026 (SCI-Expanded, Scopus)
The 8 September 2023 Mw 6.8 Al Haouz (Morocco) earthquake represents one of the most significant intracontinental events within the High Atlas, occurring at unusually deep crustal levels for a mountain belt where deformation is typically assumed to be shallow. In this study, we integrate teleseismic P- and SH-waveform inversions, regional moment tensor and high-frequency backprojection analyses to provide a comprehensive characterization of the source process and its tectonic implications. Our results indicate that the rupture started at a depth of 25 ± 2 km on a nearly E-W oriented and steeply NNW-dipping (∼71°) blind thrust fault, with a total rupture duration of approximately 10–14 s. The estimated seismic moment of 1.88 × 1019 Nm (Mw6.8) was released primarily between 15 and 30 km depth, indicating seismic failure within the lower crust. Finite-fault slip modelling reveals an asymmetric bilateral rupture with a dominant NE-SW propagation and a single main asperity. High-frequency backprojection analysis further constrains the fault geometry, showing that coherent seismic radiation originated predominantly from shallower segments (10–20 km) updip of the hypocenter, a pattern consistent with the NNW-dipping nodal plane. These findings, together with previously reported regional low b-value anomalies and independent crustal thickness constraints, suggest a mechanically strong lower crust and a high degree of lithospheric coupling beneath the Western High Atlas. The involvement of deep-seated, basement-rooted structures confirms a thick-skinned tectonic regime and highlights the critical role of inherited crustal faults in accommodating shortening within intraplate settings. These findings demonstrate the need to incorporate deep, blind fault systems into seismic hazard models for NW Africa and similar orogenic belts worldwide.