## 4 Inversion Results  
Inversion starts with the analysis of the parametric TDEM executed next to the Monzon-1 borehole (TDEM-13 parametric). According to the lithological drilling log of the Monzon-1 borehole, a seven-layer geoelectrical model with next defined thickness and depth contacts is be defined (Figure 5).  
Layer 1 consists of quaternary materials, with a thickness of 54 m. Layer 2 corresponds to continental tertiary materials of the Sarifena Formation, mainly silts, mudstones and sandstones, extending between 54 and 982 m deep. Under this layer, the materials of the Peraltilla Formation appear in layer 3, similar to the previous layer but with a higher relative proportion of sandstones. This layer extends to 1433 m depth, comprising the first meters of the Barbastro Formation, with low salt and gypsum content. Layer 4 consists of the most saline and evaportic part of the Barbastro Formation, with predominance of anhydrite and massive salty layers. The layer is 601 m thick, extending between 1433 and 2034 m deep. Layer 5 constitutes the transition layer between the bottom non saline part of the Barbastro Formation with the Red Marls Formation, up to the Jurassic, showing a thickness of 413 m. The Jurassic limestones is layer 6, located between 2447 and 2656 m depth. The last layer, layer 7, contains all the Triassic materials up to the end of the drilling, composed of clays, evaporitic materials, sandstones and limestones.  
Due to limitations of TDEM survey acquisition parameters (big loop size and measuring windows), a lack of data (ramp) on the first meter's depth is obtained, affecting the layers near the surface, so the depth of layer one (quaternary) was fixed due to the processing at close to 54 m, even thought the borehole lithological description only reflects a few meters of these materials.  
As a result of this process, an initial model based on the lithological data from the borehole and layer resistivity was obtained. The designed model obtains an RMS % fitting  
Figure 4: Decay curves in TDEM-6 with 100 stacks and 4000 stacks. Noise effect can be noticed from 8 ms in 100 stacks survey decay curve, disappearing in the 4000 stacks acquisition parameters.  
error of 0.65, indicating a good fit of the model curve based on the proposed geoelectrical model with the field data.  
There are other models equally consistent with the measured data (Figure 6B). All the equivalent models present similar results in the upper part of the data, layers 1 and 2. Additionally, the contact position between layers 2 and 3 corresponds to the hanging wall of the most saline-evaporitic part of the Barbastro Formation. The resistivity and contact position between layers 3 and 4, and the rest of the layers, shows bigger disparity between models. Taking into account that, although the equivalent models are viable from the geophysical point of view, they imply a worse correlation with the observed lithological data; these equivalent models were therefore discarded.  
Figure 5: Lithological log of Monzón-1 borehole with indication of the geoelectrical model layers position.  
Figure 6: (**A**) Apparent resistivity–time curve for parametric TDEM-13 and (**B**) geoelectrical model based on the lithological log of Monzón-1 (red) and equivalence models (dashed green lines).  
After the obtaining of the parametric model, it was applied to the rest of the TDEM resistivity-time curves (Figure 7) to obtain the geoelectric resistivity-depth columns. RMS% residuals error obtained for all the TDEM survey presents acceptable values, between 0.64-1.88%.