## 3 Results and Discussion  
### The Identification of Graphite-Rich Areas from Field IP Imaging Results at 1 Hz  
Figure 2 presents the complex conductivity imaging results for P1 (Figure 2a-d) and P7 (Figure 2e-h) in terms of in-phase and quadrature conductivity. The two profiles show different features, as measurements in P1 were conducted in the area with less graphite content, and P7 is located in the middle of the graphite quarry. Along P1, both in-phase and quadrature conductivity show the highest values in the first 100 m along profile direction; whereas for P7 the highest values are observed within the first 70 m along profile distance. Figure 2 reveals that the anomalies associated with high conductivity (\(\sigma^{\prime}\)) and polarization (\(\sigma^{\prime\prime}\)) values are one order of magnitude higher at P7 than at P1, with maximum values of \(\sigma^{\prime}>\) 200 mS/m, \(\sigma^{\prime\prime}>\) 20 mS/m in P7, and \(\sigma^{\prime}>\) 30 mS/m, \(\sigma^{\prime\prime}>\) 3 mS/m in P1. The increase in both conductivity and polarization values observed in P7 is in agreement with the geological setting, as we expect a higher graphite content in this area than in P1. Figure 2 reveals shallow inversion results with highly conductive anomalies, whereas deeper model parameters can be resolved in less conductive areas, due to the low signal-to-noise ratio (S/N) observed in highly conductive graphite rocks. Measurements in those areas are related to low voltage readings, i.e., low transfer resistances or impedance magnitudes. Such low voltage readings (\(<\)1 mV) are more susceptible to distortions due to noise associated with the galvanic contact (between electrodes and ground) and changes in the surface cover, thus resulting in low signal-to-noise ratios (S/N) observed in measurements \begin{table}
\begin{tabular}{c c c c c c} \hline
**id** & **M** & **M\({}_{\text{n}}\)** & **\(\tau\) (s)** & **L (cm)** & **V (cm\({}^{3}\))** & **\(V_{c}\) (\%)** \\ \hline plug1 & 0.96 & 0.0063 & 12.47 & 6.00 & 68.05 & 22.79 \\ plug1 cr & 0.99 & 0.0380 & 14.80 & 6.00 & 68.05 & 22.79 \\ plug2 & 0.96 & 0.0642 & 8.75 & 6.00 & 68.05 & 22.79 \\ plug3 & 0.91 & 0.0262 & 94.08 & 6.00 & 68.05 & 22.79 \\ plug3 cr & 0.96 & 0.0317 & 19.17 & 6.20 & 70.32 & 23.55 \\ plug4s & 0.50 & 0.0036 & 5.56 & 4.00 & 45.36 & 15.19 \\ plug4l & 0.55 & 0.0105 & 7.04 & 5.00 & 56.71 & 18.99 \\ \hline \end{tabular}
\end{table} 
Table 3: Cole-Cole parameter of the core plugs in terms of chargeability (M), normalized chargeability (Mn) and relaxation time, the length and volume of the plugs, and the percentage of volume covered by a plug within the measurement cell. in Zettlitz. We also note that even if the graphite provides a target with high polarization, the signal strength is dominated by the electrical impedance amplitude, i.e., the voltage-to-current ratio. Thus, high current densities injected and low voltage measurements lead to light distortions in the data due to low values in the impedance amplitude, even if the impedance phase readings are high. Besides the high conductivity of the subsurface, increasing the separation between current and potential dipoles also decreases the voltage measurements and the S/N; thus limiting the ability of surface measurements to reach deep areas. Accordingly, we observe in Figure 2 that only shallow model parameters are resolved along the first 80 m along P7 (maximum depth of investigation of ca. 2 m) at the highly conductive (>100 mS/m) zone, whereas deeper model parameters are resolved in less conductive zones between 80 m and 130 m distance. The filtering of readings with poor S/N results in the removal of a larger number of \"deep\" readings within the first half of P7, associated to large separations between the current and potential dipoles, This is observed in the imaging results with poor sensitivity below ca. 2 m depth. Accordingly, we cannot solve the highly conductive area related to the graphitic schist below the NE part of P7.