## 3 Results
Therefore, the interpretation efforts were only focused on resistivity values. The data were then inverted using both Res3 DInv (v3.20.0) and ERTLab Studio ([[http://www.geostudiastier.it/area_en.asp?idCanale=56&sezione=1](http://www.geostudiastier.it/area_en.asp?idCanale=56&sezione=1)]([http://www.geostudiastier.it/area_en.asp?idCanale=56&sezione=1](http://www.geostudiastier.it/area_en.asp?idCanale=56&sezione=1)), accessed on 27 February 2024). The calculated elevation values were estimated from GPS positioning, not extracted with a total station. The RMS was 7.69, which we interpret to be a good result for such a large volume and such a low-resistivity site. Res3 DINV was used to derive several horizontal and vertical slices (including topography). For ease of visualization and analysis, we split these geoelectrical slices into two groups: one with the shallower slices, with depths ranging from 0 to 40.9 m (Figure 8), and one with the deeper slices, ranging from 40.9 to 156.3 m (Figure 9). Already, from these slices, an area of interest can be defined. As the core interest is the mud volcano activity, this area is marked by low resistivity. In most circumstances, a contrast of around 1 ohm.m would be negligible, but given the conditions at this site, and what can be inferred from the literature, this appears to be a significant contrast area. The area becomes even more pronounced in the deeper parts of the surveyed area of the mud volcano. The area of interest (low resistivity) becomes even clearer in the deeper parts of the investigated area. Similarly, in vertical profiles (see Figure 9) extracted with RES2 DINV, an area with resistivity under 1 ohm.m is clearly delineated (in green) in the central part of the investigated area (Figure 10). Figure 7: A zoomed-in cassette (see Figure 6) showing the FullWaver data on the natural potential curve. This highlights that the natural curve is comparable in scale to the observed geoelectrical currents. Figure 8: Resistivity slices (horizontal) from the shallower part of the site. Figure 9: Resistivity slices (horizontal) from the deeper part of the site. However, Res2 DInv has significant visualization limitations and offers no straightforward way to georeference and visualize the inverted data directly. The inversion model was therefore exported and imported into ArcGIS, where it was georeferenced. This was more than simply a visualization approach. The data imported in GIS would lose a bit of detail, as the model imported contains the values and the coordinates at the center of the cell blocks of the calculated 3D inversion model resulting from the RES3 DINV. The interpolation of the points available in ArcGIS Pro is Empirical Bayesian Kriging, which in this case seems to allow for results similar to what can be visible in the RES3 DINV. Even so, it appears that there are no major changes or losses through this process, for this dataset, and ArcGIS Pro has the advantage of working with 3D models in a scene and allowing for true 3D visualizations. It also allows for creating and selecting isosurfaces (surfaces and volumes with the same resistivity) with specific values and sectioning the 3D volume in any direction, which allows for a better visualization of different areas of interest from the dataset. From the same data above, we separate several isosurfaces that are potentially indicative of the mud volcano system. It is unclear what isosurface corresponds to features of interest. However, we emphasize an isosurface of 0.8 ohm.m (Figure 11) as the first isosurface that extends from the surface down to the deeper part and that we consider to be a noteworthy surface. It is plausible (though unconfirmed) that this isosurface is indicative of the mud volcano \"plumbing\" system. Figure 10: Vertical slices also showcase a similar area of interest—an area of negative contrast, under \(1\) ohm.m. Representative vertical slices starting from 0,0. We also highlight two other isosurfaces of 1.44 and 2 ohm.m, respectively (Figure 12).