Evaluation of 3D Lithospheric Velocity Models Beneath Southern Tianshan–Tarim, China

The southern Tianshan–Tarim region marks the transition between an active orogenic belt and a relatively stable craton and is therefore important for understanding intracontinental deformation and craton–orogen interactions. We quantitatively evaluate four representative three-dimensional (3D) lithospheric velocity models—XJVM, GNVS, USTC, and CSRM—using three-component broadband records from 34 Mw 5.0–6.0 earthquakes between 2011 and 2022. Path-specific equivalent one-dimensional (1D) models are constructed from velocity profiles beneath each source and station, and synthetic seismograms are calculated using the frequency–wavenumber method. Model performance is assessed using waveform cross-correlation coefficients (CC) and time shifts for radial P (RP), transverse S (TS), and vertical P (ZP) waves in the 0.05–0.2 and 0.05–0.3 Hz bands. Mean CC values decrease from 58.3–64.3% to 53.5–61.5% as the upper frequency increases, indicating larger waveform discrepancies at higher frequencies. XJVM and USTC yield relatively high mean RP correlations, XJVM has the highest mean TS correlations, and GNVS has the highest mean and median ZP correlations in both bands. Absolute mean time shifts remain below 1 s for all models. Overall, model performance varies with frequency band and component, with no single model consistently outperforming the others across all evaluation metrics. These results provide a quantitative basis for model selection, application, and refinement in the southern Tianshan–Tarim region.