## 4 Discussion  
The observed resistivity values are substantially lower than what was expected. Despite challenging conditions, the FullWaver system appears to offer a reliable 3D method to survey this area from a geoelectrical standpoint, overcoming the difficulties. The strong injected current offered a way to obtain information from up to around a 150 m depth, which would have likely not been possible with conventional ERTs, and having a true 3D model allows for visualizing the data from different angles and areas inside the 3D model,  
Figure 11: Two isosurfaces highlighted from different angles: the 0.8 ohm.m isosurface in green (top left, top right) and the red 1.2 ohm.m isosurface (bottom left, bottom right). Figure 12: (**Top**) (left; right): the isosurfaces of 0.8 (green) and 1.44 ohm.m (yellow) visualized from two different angles. (**Bottom**) (left; right): the 2 ohm.m isosurface (purple) visualized from different angles. with higher accuracy and less interpolation biases due to the nature of the FullWaver system, as well as the spread of measured points and their direction. In our opinion, it is also important to emphasize the speed of data acquisition--the entire dataset comes from one survey day. The approach appears well suited when considering the sharp topographic variations as well. Should the distance between stations be increased, even deeper information could be obtained. As the literature only features a few examples of this methodology, and as this site is so unusual from a geoelectrical standpoint, the depth of penetration was challenging to estimate. In terms of data acquisition practices, we note that the longest amount of time was spent on deploying the mobile injection, and this can be significantly reduced with thorough planning and cables of appropriate lengths. For this type of objective, the resolution provided by this distance between stations appears to be sufficient. In fact, the distance could be increased to obtain deeper penetration at the expense of the resolution--given the investigated objective, this seems reasonable for future campaigns. This approach is particularly recommended as the negative anomaly (which is of interest) continues deeper than the investigated area. A deeper geoelectrical survey is necessary to constrain this anomaly (or another geophysical method). Nevertheless, the data presented here also highlight some areas of interest. The area of anomalously low resistivity likely corresponds to an area of mud volcano activity. Different isosurfaces, notably the one around 0.8 ohm.m, could be linked to features of interest, corresponding to the areas richest in conductive brine. The geometry of the isosurface is consistent with what would be expected from subsurface mud volcano features. If indeed indicative of mud volcano plumbing, this would suggest a mostly vertical conduit, as well as one that feeds into surface features, closer to the surface. Several elements on this isosurface also appear nearer the surface, also potentially indicating areas of activity. However, it is unclear what values would correspond to areas of volcanic activity. We expect the lowest resistivity isosurfaces to be indicative of brine-rich areas of mud volcano activity, but it is unclear what values correspond to what type of feature. The fact that this is not well constrained brings major difficulties in interpreting the geoelectrical data. Another geophysical method could offer a deeper layer of understanding regarding the structure. Nevertheless, based on geoelectrical data alone, some inferences can be made about the general subsurface structure of the mud volcano. Overall, our findings highlight only a partial correlation between the surface and subsurface structures of the mud volcano. This correlation is crucial for understanding the distribution of the subsurface dynamics of mud volcanoes. However, it is possible that we have only found one area of subsurface activity, and others may be in the yet-unsurveyed area.