The dual-source surface wave method combines active and passive seismic sources to overcome the inherent limitations of single-source methods, enabling high-resolution imaging of near-surface S-wave velocity structures. This technique represents an approach in applied geophysics for near-surface characterization. We deployed a linear array with roll-along acquisition to collocate active and passive source datasets at common receiver positions. Comparative analysis identified the extended spatial autocorrelation (ESPAC) method as optimal for dispersion extraction, given its robustness to source azimuthal variations. The accuracy of the ESPAC method in a linear array is significantly higher than that of the spatial autocorrelation (SPAC) method. Dispersion curves extracted from merged spectra underwent genetic algorithm inversion to iteratively resolve S-wave velocity profiles. The borehole-calibrated inversion results resolved high-resolution stratigraphy, including surficial soil layers and bedrock interfaces, with a depth error of less than 10% for stratigraphic boundaries, validating the methodological reliability of the method. Dual-source surveys extend the effective frequency band to 2–40 Hz, exceeding the bandwidth limitations of single-source approaches. This integration coherently merges dispersion spectra across seismic sources, reducing spectral gaps. Consequently, shallow blind zones are mitigated as the penetration depth increases, enabling continuous velocity profiling from the surface to the bedrock. Thus, comprehensive subsurface coverage is achieved across both shallow and deep zones. Linear arrays minimize site constraints and deployment complexity, improving operational efficiency as the practical configuration for mixed-source acquisition. This study demonstrates that the dual-source surface wave method is an effective approach for near-surface geophysical applications.
Yin et al. (Wed,) studied this question.