## 4 Results and Discussion
### Magnetic Prospecting  
The magnetic profiles were made in the SE-NW direction, parallel to the seismic profile and perpendicular to the SW-NE faults, with the aim of detecting them (Figure 6). After the field campaign was performed and the diurnal correction of the data was applied, despiking was carried out to eliminate environmental noise in both sectors. To obtain the total field magnetic anomaly, the value of the main magnetic field (obtained through the IGRF model) was subtracted. The result is represented in Figure 6.  
In the magnetic anomaly map of the total field, a magnetic anomaly direction of N30E is detected, on the order of 20 nT, which coincides with the trace of fault 2 deduced in the seismic profile. These are medium-wavelength magnetic anomalies (Figure 7). In other regions, equivalent anomalies have been associated to a mean-depth origin in the sedimentary basin [20]. Thus, as described in other studies [27; 28; 29; 30], fractures affecting sedimentary basins bring in contact basement and sedimentary cover materials with different magnetic susceptibility values, which would justify these linear anomalies.  
In addition to fault 2, another alignment (N60E) that corresponds to a minor order anomaly is detected (approximately 10 nT), which could coincide with the secondary fault detected in the seismic profile, as well as with the direction of the faults mapped in the Palaeozoic basement in sectors adjacent to that studied [31].  
Furthermore, in the surface representation of Figure 6, isolated anomalies of small dimensions and short wavelengths can be seen, suggesting very shallow bodies [20]. They are especially abundant towards the NE of the sector studied, in the vicinity of the road (Figure 6). All these anomalies are associated with the existence on the surface of anthropic remains with ferromagnetic elements (observed in the outcrop during measurements) that generate these small magnetic dipoles.  
Figure 7 shows two profiles of magnetic anomalies (Profile 2 and Profile 8), whose positions are indicated in Figure 6. In Profile 2, two anomalies associated with the two faults mentioned above are detected, where greater amplitudes are associated with fault 2. These two structures can be correlated with those indicated in the seismic profile of Figure 3. In Profile 8, as the two faults are very close, the magnetic anomalies appear to overlap. Anomalies of short wavelengths superimposed on the previous ones are also pointed out, suggesting very shallow bodies.  
Like previous geophysical techniques, magnetic methods are capable of detecting faults that affect both the base and the sedimentary cover, even if they are not detectable in geological mapping. In addition, the orientation of the dipoles that form these magnetic anomalies allows us to find the strike of these structures, information that had not been obtained with seismic and TDEM techniques.  
Figure 6: A map of the total field magnetic anomalies in the sector is shown in Figure 2. The positions of two of the magnetic profiles (2 and 8) are indicated, as well as the position of the seismic profile. A: small dipoles associated with ferromagnetic elements of an anthropic nature. Coordinates are in m.