## 4 Results and Discussion
### Shear Wave Velocity Models  
The inversion of the HVSR and dispersion curves allowed for estimating the shear wave velocity in the soil sedimentary layers. The inversion process relied on borehole data (Table 1), geological information (Figure 2), and velocity values derived from previous studies conducted in the same basin [6, 32, 33, 45]. Figure 7b and Figure 8 (right panel) show the shear wave velocity profiles obtained from the best-fit 1D Vs model through the inversion of the dispersion and HVSR curves, respectively. The observed HVSR curve was compared to the theoretical Rayleigh wave ellipticity curve for each model, using a misfit value. The plots depict the model with the best fit (minimum misfit), represented by a black line, as an indicator of the confidence associated with the results. The dark gray area outlines solutions within 10% of the minimum misfit, while the light gray curves illustrate the other models considered during testing. Figure 7: (a) Obtained Rayleigh wave dispersion curves. The dark gray band represents dispersion curve solutions for a minimum misfit of +10%. Light gray represents all of the generated solutions. The two black lines represent the observed (black dotted lines) and the calculated (with minimum misfit) dispersion curves. (b) The calculated Vs models (thick black line). The dark gray band represents Vs models with a minimum misfit of +10%. Light gray represents all of the generated models. The model with the minimum misfit is represented with a black line. As a result of the inversion of the HVSR and dispersion curves, the thickness and velocity of each layer were obtained. These results allowed for plotting six cross-sections, as shown in Figure 9a. In addition, Figure 9b shows the correspondence between the fundamental frequency and the HVSR points, as a function of the corresponding amplitude. The lithological boreholes revealed four sedimentary layers corresponding to Quaternary, Pliocene, Upper Miocene and Middle Miocene deposits. Vs models derived from HVSR curves were used to estimate the thickness and shear wave velocities (Vs) of these layers within the soil column. In addition, the dispersion curves were used to determine the sedimentary thickness and Vs values for the upper 30 m of the soil profile. Figure 9 presents three cross-sections oriented WWW-ESE and 3 others oriented SSW-NNE (a, c, e, g, i, k). These cross-sections indicate good agreement between the depth of the sedimentary layers and their corresponding frequency peaks, represented by the contour maps (b, d, f, h, j, l). Note that a low frequency indicates a deep sedimentary layer. This figure also demonstrates a clear increase in the depth of the sedimentary layer following the SSW-NNE direction. Figure 8: Some results of the inversion of the HVSR curves. (**Left**) Experimental HVSR curves represented by black dotted lines and fitted to the theoretical curve represented by red lines. (**Right**) Estimated Vs models (black line). The dark gray band represents Vs models with a minimum misfit of +10%. Light gray represents all of the generated models. The model with the minimum misfit is represented with a black line in the right panels. Figure 9: Cont. Figure 9: Cross-sectional profiles (**left panels**: **a,c,e,g,i,k**) illustrating the lateral variations in geological layers, with corresponding HVSR contour plots (**right panels**: **b,d,f,h,j,l**) displaying the fundamental frequency distributions and amplitude variations. The left panels depict subsurface stratigraphy along profiles 4, 5, and 6, showing sedimentary and bedrock layers with their respective shear wave velocities. Measurement points (red triangles) and geotechnical data locations (red squares) are also indicated. The right panels (**b,d,f,h,j,l**) present the spatial distributions of fundamental frequency derived from HVSR analysis, with amplitude variations represented by color gradients. The highest amplitude regions in the HVSR plots align with the depth variations of the bedrock layers in the geological cross-sections.