GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.2 GNGTS 2024 Figure 2 - Maps of the geophysical surveys carried out at the HydroGeosITe, with the perimeter of the area always accessible indicated in blue (HGS in the legend). Top lef – Ground TEM soundings with 40x40 m 2 (blue squares) 100x100 m 2 (yellow) and 200x200 m 2 (magenta square) loop sizes. Top right – DCIP profles with 10 m spacing (doted orange lines, ≈ 4 km) and 5 m spacing. Botom lef – SkyTEM312 2021 soundings displayed by green-dots, while SkyTEM306HP 2023 soundings are displayed with marine-green lines for all the three diferent fight heights. Botom right – tTEM soundings; approximately the same area has been covered with the Loupe system 3. Data Modelling and Joint inversion Inductve and galvanic data give usually signifcantly diferent inversion models, due to their diferent sensitvity to the resistvity distributon. Ofen resistvity anisotropy is used to justfy the lack of accordance between the two methods (e.g. Christansen et al., 2007), even if recent publicatons have shown compatbility between AEM and galvanic data (Christensen, 2022), but without considering the induced polarizaton efect. However, Fiandaca et al. (2022) have shown that the IP phenomenon has a strong efect on inductve data also in environmental applicatons, with signifcant dependence of the efect on the system characteristcs. Following these fndings, we propose frst a comprehensive interpretaton of the independent models, then the employment of joint inversion scheme to retrieve a unique model from both galvanic and inductve data taking into induced polarizaton. In partcular, all the inversions are carried out following Fiandaca et al. (2024) with EEMverter, a sofware specifcally designed for modelling IP in joint inductve/galvanic inversions. EM data are modelled in 1D, while the galvanic