<p>A comprehensive understanding of the geological structure and site seismic response mechanisms of landslides is crucial for evaluating landslide hazards, guiding seismic design, and improving engineering protection measures. In this study, mixed-source surface wave imaging was used to construct three 2-D shear wave velocity profiles along three survey lines of the Majiagou landslide, which were integrated with previous embedded-borehole monitoring results and borehole data to systematically reveal its 2-D stratigraphic structure and seismic response mechanism. Based on high-resolution 2-D shear wave velocity structure and geological calibration with borehole data, a four-layer geological structure of the Majiagou landslide was identified and precisely delineates the sediment layer thickness and bedrock transition zones through a “velocity threshold-geological interface-spatial morphology” framework. An innovative integration of monitoring results from embedded boreholes with imaging results from mixed-source surface waves is presented, which expands the sliding surface analysis of the Majiagou landslide from 1-D points to 2-D surfaces. The geometric forms of two sliding surfaces were identified in the 2-D space of the Majiagou landslide, which significantly enhances the spatial continuity and accuracy of the sliding surfaces. Finally, by combining 2-D high-resolution structure of shear wave velocity with borehole data, the natural frequencies and seismic amplification factors at different locations of the landslide were calculated, addressing the limitations of embedded-borehole monitoring techniques in analyzing seismic responses of heterogeneous landslide sites and revealing variations in seismic stability across different areas of the Majiagou landslide. Key theoretical foundations and practical guidance for detecting and analyzing similar deep-seated landslides are provided.</p>