GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.2 GNGTS 2024 DC and full-decay IP data are modelled in 2D (Fiandaca et al., 2013) in terms of the maximum phase angle (MPA) Cole-Cole re-parameterizaton (Fiandaca et al., 2018). The objectve functon of the inversion is defned as: (1) Where and are the numbers of data (both inductve and galvanic) and roughness constraints (on the unique joint model ), respectvely, and the balance between inductve and galvanic data is achieved through their standard deviaton . The independent inversions have been carried out with the same forward schemes of the joint inversion, but using only one data type at once. All data have been processed in EEMstudio (Sullivan et al., 2024) for culling outliers out before inversion. Both the geophysical galvanic and inductve models exhibit concordance with each other and display features likely consistent with the geological-stratgraphic characteristc of the area. The joint models derived from incorporatng both E & EM data within a unifed inversion framework, not only confrm the primary structures defned by the independent models but also signifcantly enhance the resistvity model resoluton, as shown in Figure 3. Figure 3: Inversion models of the crossing North-South and West-East profles obtained through inductve-only AEM and ground TEM data (lef), joint AEM-Ground EM-tTEM-DCIP data (center) and galvanic-only DCIP data (right), with full profle view in the top panels and zoom-in close to the crossing point in the botom panels. The lithological descripton of a borehole near to the profles is shown in color bars; for helping the comparison between borehole informaton and inversions, the borehole has been projected from its true positon to the crossing point of the profles. Ground EM, SkyTEM, tTEM sounding positons and electrodes are indicated with the same color coding of Figure 2 Q = 1 N d + N r N d ∑ i =1 ( d obs − d forward ) σ 2 d i 2 + + N r ∑ i , j ( m i − m j ) σ 2 r i , j 2 1 2 N d N r d obs m σ 2 d