Strain partitioning across the Sabzevaran–Jiroft fault system at the Zagros–Central Iran–Makran transition

The Zagros–Central Iran–Makran transition zone represents a key segment of the Arabia–Eurasia collision system, where deformation is transferred from continental collision to oceanic subduction domains. Despite its geodynamic importance in the broader context of Asian tectonics, the kinematic architecture and seismotectonic behavior of fault systems within this transfer zone remain incompletely constrained. Here, we present an integrated structural–seismological analysis of the Sabzevaran and Jiroft fault systems, two major N–S-trending fault zones that accommodate part of the ongoing convergence between the Arabian and Iranian plates. Our approach combines detailed field-based structural mapping with microseismicity data derived from dense local seismographic networks to resolve fault geometry from surface to depth. The results reveal that the Sabzevaran–Jiroft fault system is composed of multiple sub-parallel fault strands exhibiting systematic variations in kinematics, including pure strike-slip, pure thrust, and oblique-slip mechanisms. This spatial partitioning of deformation is further supported by the distribution of microearthquake hypocenters, which show a progressive increase in focal depth toward the north and northeast, delineating a transition from shallow crustal deformation to deeper lithospheric processes. We propose a refined strain-partitioning model in which deformation within the transfer zone is accommodated by coexisting strike-slip and thrust fault networks that evolve along a geometrically segmented system. The divergence of the Sabzevaran and Jiroft faults toward the south, coupled with their parallel arrangement in the north, reflects a dynamic linkage between inherited structures and ongoing plate-scale stresses. Our findings provide new insights into the mechanical coupling between the Zagros collision zone and the Makran subduction system, highlighting the role of transfer zones in redistributing strain across the Arabia–Eurasia plate boundary. This study advances the understanding of fault interaction, deformation partitioning, and seismic hazard potential in one of the most tectonically active regions of western Asia, and offers a transferable framework for analyzing similar transition zones worldwide.