The Main Recent Fault (MRF) is a major strike-slip fault system within the Zagros collision zone, having generated several destructive earthquakes in western Iran. However, the subsurface architecture of the Silakhur region remains poorly constrained. This study applies local earthquake tomography to investigate the three-dimensional crustal velocity structure beneath the Silakhur region, northwestern Zagros. The analysis is based on aftershock data recorded by two temporary seismic networks deployed following the 2006 Mw 6.1 Silakhur earthquake. A total of 335 well-constrained aftershocks were inverted using the LOTOS algorithm to derive P-wave and S-wave velocity models of the upper crust. The tomographic results reveal significant lateral velocity heterogeneity associated with major tectonic structures. A major velocity boundary coincides with the mapped trace of the Doroud Fault, indicating strong structural control on crustal velocity distribution. A prominent low-velocity zone is imaged beneath the central Silakhur Plain, broadly following the Abi-Diz River and overlapping with areas previously interpreted as concealed fault-related structures. Additional velocity discontinuities along the northern margin of the plain correspond to a previously proposed concealed fault zone. Comparison with regional geological observations indicates a close relationship between seismic velocity variations and geological structure. The spatial correspondence between velocity anomalies and mapped or inferred fault systems suggests that the reconstructed velocity model captures the principal tectonic features of the Silakhur region. The results provide independent geophysical constraints on fault-controlled deformation and support previous interpretations suggesting the development of a pull-apart basin within this segment of the Main Recent Fault system.