## 4 Results
### La Torrecilla  
Figure 7a shows the resistivity model, Figure 7b shows the \(\rm{Vp}\) model, Figure 7c shows the \(\rm{Vs}\) model, and Figure 7d illustrates a combined interpretation of three geophysical data. The resistivity and seismic velocity models obtained from the La Torrecilla profile reveal distinct domains in the shallow subsurface. The CZ is represented by a high resistivity area (\(\rho>200\) m) to the SE of the profile (Figure 7a), which is consistent with the expected high resistivity of Quaternary alluvial fan deposits and fluvial sediment composed of conglomerates, gravels, sands, silts, and clays. Another high resistivity area is identified at surface levels at a distance of 0 to 450 m along with the profile. Underneath the high resistivity area, a medium resistivity area (50-150 \(\rm{\Omega m}\)) corresponds to the Paleozoic basement. At distances of 450 to 550 m, there is a \(\sim\)500 m wide low resistivity (\(\rho<50\)\(\rm{\Omega m}\)) that features net and parallel limits. This sector is interpreted as a wide fault zone between two fault planes (Figures 1 and 2) belonging to the AMF shear deformation zone. This shear zone is formed by a 20 m wide band of well-developed fault gouge in Permian-Triassic quartzites and phyllites from the Alpujarride Complex together with sheared Upper Neogene marks, sandstones, and conglomerates.  
Figure 7b,c show the \(\rm{Vp}\) and \(\rm{Vs}\) distributions, respectively. Both models show a low seismic velocity subparallel to and near the surface. The CZ is characterized by a low seismic velocity (\(\rm{Vp}<1300\) m/s and \(\rm{Vs}<600\) m/s) with thickness variation in the  
Figure 7: Geophysical imaging of the La Torrecilla with the interpretation proposed and details. Black line indicates the thickness of the CZ. (**a**) The resistivity profile, (**b**) the \(\rm{Vp}\) profile from first arrival \(\rm{P}\)-wave tomography, (**c**) the \(\rm{Vs}\) profile from MASW, and (**d**) a joint comparison of the CZ inferred from the different geophysical methods. The dot-yellow pattern is shown when the three methods match in their interpretations. The low-velocity anomaly (limited between F1 and F2) corresponds to the AMF shear deformation zone [49]. The variation in thickness of the CZ is indicated by h1, h2, and h3.  
NW-SE direction of 30-40 m at a distance of ca. 300 m (h1), which increases by 50-60 m at a distance of ca. 530 m (h2), and thins again to 30-35 m at a distance of ca. 980 m (h3). At the same distance, the CZ interpreted by Vp and Vs (Figure 7b,c) also appears to match the distribution of the high resistivity in Figure 7a (\(\rho>200\)\(\Omega\)m). These low velocities correspond to the Quaternary fluvial sediments, alluvial fan deposits and sedimentary rocks in the southern half of the profile, south of the shear zone. At a distance of ca. 400-500 m, there is a fault zone that is relatively parallel to Figures 1 and 2, which is represented by a discontinuity low-velocity layer. Bedrock layers characterized by values of Vp \(>\) 1300 m/s and Vs \(>\) 600 m/s were interpreted as more compact and rigid rock formations, i.e., the fresh bedrock that underlies the CZ. These Vp, Vs, and resistivity values are in line with those recorded in the well-logs of the FAM-1 borehole (Figure 3).