Electrical and Electromagnetic Geophysical Prospecting for the Monitoring of Rock Glaciers in the Dolomites, Northeast Italy

Abstract

The monitoring of rock glaciers plays a relevant role in relation to natural hazards in high mountain environments. Due to the climate warming, mountain permafrost is thawing, and its degradation is influencing the triggering and the evolvement of processes such as rockfalls, landslides, debris flows and floods. Therefore, the study and monitoring of these periglacial forms have both a scientific and economic importance. We tested electrical and electromagnetic measurements along the same investigation lines, in two different sites of the Dolomites area (Northeast Italy). Electrical prospecting exploits the high resistivity contrast between frozen and non-frozen debris. However, these measurements have high logistic demands, considering the complex rock glaciers surface and the need of ground galvanic contact. For this reason, we tried to compare electrical measurements with electromagnetic contactless ones, that theoretically can be used to define the distribution of electrical resistivity in the first subsoil in a quicker and easier way. The obtained results show that the joint use of the two methods allows us to characterize a rock glacier subsoil with good confidence. Finally, the advantages and disadvantages of both the techniques are discussed.

Detection of soil pipe network by geophysical approach: Electromagnetic induction (EMI) and electrical resistivity tomography (ERT)

“…Generally, the electromagnetic methods are more complicated, and the data are more sensitive to distortions, for example, electronic instrumental drift, unintentional heterogeneous height and orientation of the device during field survey, variations of ground surface cover (e.g., vegetation height), and an abundance of macropores in the near surface. This is in line with recent studies of rock glaciers in the Dolomites (Pavoni et al, 2021),…”

“…These findings correspond with the latest study by Wodajo et al (2021), who stated that EMI provides zoning information on soil piping susceptibility, but it only narrows down the locations for more focused and intrusive investigation. It is in line with studies done in different geomorphological contexts, for example, rock glaciers, where also EMI has been suggested for use as an instructive method to extend, in a quick and convenient way, the information derived from the more accurate ERT technique (Pavoni et al, 2021). This study has proved that the use of at least two geophysical methods (here EMI and ERT) may give a sufficient insight to avoid misinterpretation as already underlined in geomorphological studies (Schrott & Sass, 2008).…”

“…This problem does not occur during ERT measurements as the electrodes are set up in the ground, and they are not moved during the survey. This also implies that the data of ERT and EMI cannot be directly compared, as has been already mentioned and reported by Pavoni et al (2021).…”

Stress-Electromagnetic Radiation (EMR) Numerical Model and EMR Evolution Law of Composite Coal-Rock under Load

“…EMR comes from the electromagnetic field, which is essentially a wave energy. Electromagnetic field includes electric field and magnetic field, and the two excitation energy values are equal , so the study of EMR only needs to consider the change of electric field without the magnetic field. As an important physical quantity of electric field, the variation of electric field intensity can be used to represent the variation of EMR.…”

Electromagnetic Induction Is a Fast and Non-Destructive Approach to Estimate the Influence of Subsurface Heterogeneity on Forest Canopy Structure

“…While at the same time, ERT hardly exceeds four cross-sections, but provides a more detailed view of the geoelectric properties' distribution in depth. The combination of ERT and EMI is widely used in other fields [28][29][30][31], because EMI allows to investigate large areas and to spatially expand some of the interpretations from ERT.…”