## 5 Implications and Discussion  
### The Advantages of Multi-Geophysical Measurements and Implications for the Interpretation of the CZ  
Geophysical methods have numerous advantages for the characterization of the near-surface in terms of cost efficiency and depth accuracy (e.g., [76; 77]). Geophysical methods can provide spatial boundaries to determine the maximum depth range of the CZ [22; 23; 78]. When deep marker information (e.g., well data) is not available,  
Figure 10: Geophysical imaging of Carrascoy site with the interpretation proposed and details. (**a**) The Vp model from seismic tomography, (**b**) the Vs model from MASW, and (**c**) a joint comparison of the interpreted CZ from both geophysical models. The low-velocity anomalies marked by F1 and F2 correspond to different thrust strands of the ACNF. can be combined with different geophysical methods to produce a robust model of the near-surface. For instance, P-wave tomography, Multichannel Analysis of Surface Waves (MASW), and Electrical Resistivity Tomography (ERT) are here used to minimize the ambiguity of the subsurface features. Each geophysical method used to determine the thickness of the CZ produces varying results in terms of vertical and lateral resolution. One approach involved the combination of the interpretation results from the multi-geophysical method to use the minimum thickness constrained by all the data as the final interpretation (as seen in, e.g., [74; 75]). Future work could address the integration of the geophysical data using more advanced interpretation strategies, e.g., Machine Learning [79] or joint inversion [80]. Taking into account that the seismic profiles were originally designed for seismic reflection characterization, the quality of the first arrivals ensures the homogeneous distribution of the ray coverage along all profiles. It is important to highlight that the areas of poor coverage/gaps in ray coverage observed in some resulting velocity models (e.g., La Torrecilla, Figure 7b, and La Salud South, Figure 9a) are not related to the lack of data, but to the fact that these areas the acquisition geometry is far from a 2D geometry (mainly due to crooked pathways). The use of a fully 3D inversion code makes it difficult to obtain a good ray coverage in these areas when extracting the 2D velocity model along the seismic profile transects. The interpretation of the CZ thickness in the La Torrecilla profile (Figure 7d) differs the most at ca. 250 m, where the ERT results point to a thicker CZ than the Vp and Vs models (h1). The three geophysical methods meet at a distance of ca. 620 m to provide the same thickness interpretation (h2). Meanwhile, at a distance of ca. 900 m, the ERT interpretation results matched Vp and shows a thicker CZ than that interpreted by Vs. Generally, the interpretation of Vs from MASW represents the distribution of the thickness of the CZ in the La Torrecilla profile as a minimum thickness than Vp and ERT. In the case of the La Salud North profile in Figure 8d, the interpretation of the Vp model represents the distribution of the CZ. The interpreted thickness of the CZ in the Vp model is slightly thinner than in the Vs model, and the result of the ERT interpretation is the thickest. The three geophysical methods meet in h1 at a distance of ca. 100 m and ca. 900 m facing SE. Meanwhile, Vp and Vs match in h2 at a distance of ca. 350 m and h3 at a distance of ca. 750 m.  
From the La Salud South profile, the geophysical interpretation of the thickness of the CZ was obtained from the combination of Vp and Vs models (Figure 9c). The resulting CZ interpretation of the Vp model is slightly thinner than Vs and meets at some points, such as h1 at a distance of approximately 200 m and h3 at approximately 1300 m. In the Carrascoy profile (Figure 10c), the interpretation of the CZ is determined by the Vs result, similarly to the La Torrecilla profile (Figure 7d). The resulting interpretation of Vs is slightly thinner than Vp and meets at some points, such as h1 at a distance ca. 600 m and h3 at a distance ca.