3D Structural Characterization and Analogue Modeling to Constrain the growth and evolution of the Yusuf Fault (Alborán Sea)

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Abstract
The Yusuf Fault system (YF) is one of the largest active strike-slip structures in the Alborán Sea, where it acts as a lithospheric-scale boundary accommodating part of the NW-SE convergence between the Nubian and Eurasian plates. It trends WNW-ESE, extends for ~150 km, and is characterized by a complex fault array and a prominent pull-apart basin. Accurate representation of its 3D geometry and seismogenic behavior is essential to constrain its seismic potential and understand the tectonic evolution of the region. In this study, we integrate multibeam bathymetry, high-resolution multi-channel seismic reflection (HR-MCS) data, and scaled analogue modeling to characterize the structural architecture and kinematic evolution of the YF. Bathymetric analysis using topographic attributes enabled detailed mapping of the fault trace and associated geomorphic features, while seismic data interpretation revealed subsurface discontinuities and fault offsets affecting key seismostratigraphic units from the Upper Miocene to the Quaternary. This information allowed us to construct the first 3D structural model of the YF, showing that the system consists of multiple overlapping segments forming a complex strike-slip fault architecture. To explore the processes controlling pull-apart basin development, we conducted analogue experiments simulating strike-slip fault interaction. Results suggest that basin opening is controlled by overlapped fault geometry and lateral displacement rates, providing a physical framework for interpreting the observed morphostructural patterns. This integrated approach improves constraints on fault growth and segmentation, offering critical input for seismic hazard models in the western Mediterranean.