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Recently, there has been increasing interest in organic carbon (OC) certification of soil as an incentive for farmers to adopt sustainable agricultural practices. In this context, this pilot project combines geochemical and geophysical methods to map the distribution of OC contents in agricultural fields, allowing us to detect variations in time and space. Here we demonstrated a relationship between soil OC contents estimated in the laboratory and the apparent electrical conductivity (ECa) measured in the field. Specifically, geochemical elemental analyses were used to evaluate the OC content and relative isotopic signature in collected soil samples from a hazelnut orchard in the Emilia–Romagna region of Northeastern Italy, while the geophysical Electromagnetic Induction (EMI) method enabled the in situ mapping of the ECa distribution in the same soil field. According to the results, geochemical and geophysical data were found to be reciprocally related, as both the organic matter and soil moisture were mainly incorporated into the fine sediments (i.e., clay) of the soil. Therefore, such a relation was used to create a map of the OC content distribution in the investigated field, which could be used to monitor the soil C sequestration on small-scale farmland and eventually develop precision agricultural services. In the future, this method could be used by farmers and regional and/or national policymakers to periodically certify the farm's soil conditions and verify the effectiveness of carbon sequestration. These measures would enable farmers to pursue Common Agricultural Policy (CAP) incentives for the reduction of CO2 emissions. [ABSTRACT FROM AUTHOR]

Infrastructure bridges play a crucial role in fostering economic and social development. However, the adverse effects of natural hazard and weather degradation, coupled with escalating rates of traffic, pose a significant threat. The resultant strain on the structure can lead to undue stress, elevating the risk of a critical asset failure. Hence, non-destructive testing (NDT) has become indispensable in the surveillance of bridge infrastructure. Its primary objectives include ensuring safety, optimizing structural integrity, minimizing repair costs, and extending the lifespan of bridges. NDT techniques can be applied to both existing and newly constructed bridge structures. However, it is crucial to recognize that each NDT method comes with its own set of advantages and limitations tailored to specific tasks. No single method can provide an effective and unequivocal diagnosis on its own. Among the various NDT methods, Ground Penetrating Radar (GPR) has emerged as one of the most widely employed techniques for monitoring bridges. In fact, recent technical regulations now mandate the use of GPR for bridge monitoring and characterization, underscoring its significance in ensuring the structural health and longevity of these critical infrastructures. Ground Penetrating Radar (GPR) stands out as one of the most highly recommended non-destructive methods, offering an efficient and timely assessment of the structural conditions of infrastructure. Recognizing the pivotal role of non-destructive testing (NDT) in this context, this paper aims to elucidate recent scientific endeavors related to the application of GPR in bridge engineering structures. The exploration will commence with a focus on studies conducted both at the model level within laboratory settings and on real cases. Subsequently, the discussion will extend to encompass the characterization and monitoring of the bridge's main elements: slab, beam, and pillar. By delving into these scientific experiences, this paper intends to provide valuable insights into the efficacy and applicability of GPR in assessing and ensuring the structural integrity of bridges. This paper provides a concise survey of the existing literature on the application of Ground Penetrating Radar (GPR) in the assessment of bridges and viaducts constructed with masonry and reinforced concrete, taking into account papers of journal articles and proceedings available on open databases. Various approaches employed in both laboratory and field settings will be explored and juxtaposed. Additionally, this paper delves into discussions on novel processing and visualization approaches, shedding light on advancements in techniques for interpreting GPR data in the context of bridge and viaduct evaluations. [ABSTRACT FROM AUTHOR]

Steel rebar corrosion is one of the main causes of the deterioration of engineering reinforced structures. Steel rebar in concrete is normally in a non-corroding, passive condition, but these conditions are not always achieved in practice, due to which corrosion of rebars takes place. This degradation has physical consequences, such as decreased ultimate strength and serviceability of engineering concrete structures. This work describes a laboratory test where GPR and SP geophysical techniques were used to detect and monitor the corrosion phenomena. The laboratory tests have been performed with several reinforced concrete samples. The concrete samples were partially submerged in water with a 5% sodium chloride (NaCl) solution. Therefore, an accelerated corrosion phenomenon has been produced by a direct current (DC) power supply along the rebar. The geophysical measurements were performed with a 2.0 GHz centre frequency GPR antenna along several parallel lines on the samples, always being the radar line perpendicular to the rebar axis. The GPR A-scan amplitude signals were elaborated with the Hilbert Transform approach, observing the envelope variations due to the progress of the steel rebar corrosion in each concrete sample. Moreover, Self-Potential acquisitions were carried out on the surface of the concrete sample at the beginning and end of the experiments. Each technique provided specific information, but a data integration method used in the operating system will further improve the overall quality of diagnosis. The collected data were used for an integrated detection approach useful to observe the corrosion evolution along the reinforcement bar. These first laboratory results highlight how the GPR should give a quantitative contribution to the deterioration of reinforced concrete structure. [ABSTRACT FROM AUTHOR]

The Tramutola area in the High Agri Valley represents a key for the Southern Apennines fold and thrust belt. There, natural oil seeps from small carbonate reservoirs located at shallow depths that have been historically known since the 19th century, and hypothermal water was discovered during hydrocarbon exploration. From a geological point of view, the study area, extending for about 11 km2, is characterized with the presence of a complete section of the tectonic units of the southern Apennines and a complex structural framework that has not yet been fully clarified. In this work, geological analysis is based on new lithological and structural data, acquired during a detailed geological survey, compared with well logs obtained during exploration for hydrocarbons. Furthermore, a new geophysical investigation down to a 1 km depth (deep electrical resistivity tomography) allowed inference of buried structural and geological characteristics of the studied area. Through combining surface and subsurface data, some preliminary considerations about the structural setting and geofluid presence down to a 1 km depth have been made. Furthermore, geological–structural cross-sections have been constructed with the purpose of depicting the geometries of structures affecting the Apennine nappe pile in the subsurface, possibly favoring early uprising of hydrocarbons as well as circulation of hypothermal fluids and associated gases rising from deeper reservoirs. [ABSTRACT FROM AUTHOR]

The increasing use of geophysical investigations for archaeological purposes is now provided also by Italian reforms about preventive archaeology. They allow not only the discovery or the spatial definition of possible buried archaeological evidence, but they are also able to define the state of preservation of ancient structures. The Bocca delle Menate archaeological site is in Comacchio village territory, situated in Ferrara provence (Emilia Romagna region, Italy). The archeological site provides important evidence of the Roman presence in the Po Delta (Italy). The Roman villa was excavated between 1958 and 1959, during the reclaiming works in the Mezzano Valley (Comacchio, Ferrara). An archaeological preliminary survey and a geophysical field trip using Geomagnetic and Frequency Domain Electromagnetic Methods were carried out, following the aim to identify the planimetry of the villa previously excavated and eventually newly discovered archaeological remains. The geomagnetic results detected the archaeological buried structures, even if the original disposition of them is not completely highlighted. The electromagnetic method was able to depict the geological and geomorphological background surrounding the Roman villa. The obtained results highlighted that the applied geophysical methods are excellent tools for the preservation, protection, and monitoring of archaeological heritage previously excavated, adding to their already known importance as best tools for new archaeological buried remains detections. [ABSTRACT FROM AUTHOR]

Electrical Resistivity Tomography (ERT) is a robust and well-consolidated method largely applied in near-surface geophysics. Nevertheless, the mapping of the spatial resistivity patterns of the subsurface at a depth greater than 1 km was performed in just a few cases by the ERT method, called deep ERT (DERT). Since, in many cases, the term DERT was adopted with ambiguity for geoelectrical explorations varying in depth within a range of 0–500 m, the main goal of this review is to clearly define the DERT method, identifying a threshold value in the investigation depth. The study focuses both on the purely methodological aspects (e.g., geoelectrical data processing in low noise-to-signal ratio conditions; tomographic algorithms for data inversion) and on the technological features (e.g., sensor layouts, multi-array systems), envisaging the future directions of the research activity, especially that based on machine learning, for improving the geoelectrical data processing and interpretation. The results of the more significant papers published on this topic in the last 20 years are analyzed and discussed. [ABSTRACT FROM AUTHOR]

Hydrocarbons represent one of the most dangerous sources of contamination for environmental resources. Petroleum contaminants released from leaking fuel storage tanks or accidental spillages represent serious worldwide problems. Knowledge of the contaminant distribution in the subsoil is very complex, and direct measurements, such as boreholes or drillings, are strongly required. Even if the direct measurements define accurate information, on the contrary, they have low spatial coverage. Geophysics can effectively support conventional methods of subsoil sampling by expanding the information obtainable, providing to analyze, with higher resolution, larger areas of investigation. Consequently, different geophysical techniques have been used to detect the presence and distribution of hydrocarbons in the subsurface. Electrical resistivity tomography is an efficient geophysical methodology for studying hydrocarbon contamination. Indeed, this methodology allows for the reduction of the number of drillings or soil samples, and several papers described its success. One of the advantages is the possibility to successfully perform analyses in time-lapse to identify the degradation of the contaminants. Indeed, natural attenuation of hydrocarbon contaminants is observed under aerobic conditions due to biodegradation, which should be the principal phenomenon of physical variations of the subsoil. Therefore, a laboratory experiment was conducted in a sandbox to simulate a spillage of common diesel occurring in the vadose zone. The sandbox was monitored for a long period (1 year, approximately) using time-lapse cross borehole electrical resistivity tomographies. Results highlight the usefulness of in-hole electrical tomography for characterizing underground hydrocarbon leakage and the variability of the subsurface physical behavior due to contaminant degradation. Therefore, the experiment demonstrates how the electrical method can monitor the biodegradation processes occurring in the subsoil, defining the possibility of using the methodology during remediation activities. [ABSTRACT FROM AUTHOR]

Featured Application: In this work, Vector Autoregressive and Recurrent Neural Network algorithms are used to predict time-space evolution of a saline water plume in homogeneous and real aquifers. In this paper, an integrated workflow aimed at optimizing aquifer monitoring and management through time-lapse Electric Resistivity Tomography (TL-ERT) combined with a suite of predictive algorithms is discussed. First, the theoretical background of this approach is described. Then, the proposed approach is applied to real geoelectric datasets recorded through experiments at different spatial and temporal scales. These include a sequence of cross-hole resistivity surveys aimed at monitoring a tracer diffusion in a real aquifer as well as in a laboratory experimental set. Multiple predictive methods were applied to both datasets, including Vector Autoregressive (VAR) and Recurrent Neural Network (RNN) algorithms, over the entire sequence of ERT monitor surveys. In both field and lab experiments, the goal was to retrieve a determined number of "predicted" pseudo sections of apparent resistivity values. By inverting both real and predicted datasets, it is possible to define a dynamic model of time-space evolution of the water plume contaminated by a tracer injected into the aquifer system(s). This approach allowed for describing the complex fluid displacement over time conditioned by the hydraulic properties of the aquifer itself. [ABSTRACT FROM AUTHOR]

Geophysical techniques are widely applied in the archaeological field to highlight variations of the physical behaviour of the subsoil due to the presence of ancient and buried remains., Considerable efforts are required to understand the complexity of the relationship between archaeological features and their geophysical response where saturated conditions occur. In the case of lacustrine and wetland scenarios, geophysical contrasts or electromagnetic signal attenuation effects drastically reduce the capabilities of the geophysical methodologies for the detection of structures in such conditions. To identify the capability of the electrical and electromagnetic methods in different water-saturated scenarios, an experimental activity was performed at the Hydrogeosite CNR laboratory. The test allowed us to analyze the limits and potentialities of an innovative approach based on the combined use of the ground-penetrating radar and 2D and 3D electrical resistivity tomographies. Results showed the effectiveness of the ground-penetrating radar for detecting archaeological remains also in quasi-saturated and underwater scenarios despite the em signal attenuation phenomena; whilst the results obtained involving the resistivity tomographies offered a new perspective for the archaeological purposes due to the use of the loop–loop shaped array. Moreover, the radar signal attenuation, resolution and depth of investigation do not allow to fully characterize the archaeological site as in the case of the scenarios with a limited geophysical contrast (i.e., water-saturated and arid scenarios). The experimental tests show that these limits can be only partially mitigated through the integration of the geophysical methodologies and further efforts are necessary for improving the results obtainable with an integrated use of the adopted geophysical methodologies. [ABSTRACT FROM AUTHOR]

Non-destructive tests are strongly required in engineering applications for monitoring civil structures. The use of compared and integrated innovative approaches based on geophysical methodologies represents an effective tool for the characterization and monitoring of reinforced concrete (RC) structures. Therefore, the main aim of the work was to improve the knowledge on the potentiality and limitations of the Ground Penetrating Radar (GPR) and the Electrical Resistivity Tomography (ERT) with electrodes disposed both on the surface and in the boreholes. The work approach was adopted on an analog model of a reinforced concrete frame built ad hoc at the Hydrogeosite Laboratory (CNR-IMAA), where simulated experiments on full-size physical models are defined. Results show the ability of an accurate use of GPR to reconstruct the rebar dispositions and detect in detail possible constructive defects, both highlighting the lack of reinforcements into the nodes and providing useful information about the safety assessment of the realized structure. The results of the ERT method defined the necessity to develop ad-hoc electrical resistivity methods to support the characterization and monitoring of buried foundation structures for civil engineering applications. Finally, the paper introduces a new approach based on the use of cross-hole ERTs (CHERTs) for the engineering structure monitoring, able to reduce the uncertainties usually affecting the indirect results. [ABSTRACT FROM AUTHOR]

The Metaponto coastal plain extends about 40 km along the Ionian coast, between the Sinni and Bradano Rivers (southern Italy). During the 20th century, the increases in modern irrigation systems, land reclamation works, the overexploitation of wells, and agricultural and industrial activities have deeply modified land use and groundwater availability and quality along the plain. These modifications negatively impacted the natural systems in terms of groundwater and soil salinization, magnifying the risks due to seawater intrusion. In this study, we explored the proneness to seawater intrusion, testing a multidisciplinary approach based on hydrochemical and geophysical investigations. A significant portion of the coastal plain was selected for this purpose. A set of 49 groundwater samples was analyzed to define the chemical characteristics of the water and geoelectrical measurements were recorded along three long profiles. The geoelectrical surveys showed in detail the aquifer bottom pattern where it is deeply incised by paleovalleys, defining the main hydrostratigraphic features, as it is necessary to prevent seawater intrusion worsening. The hydrochemical data highlighted areas with higher seawater intrusion proneness. The acquired measurements show the high proneness to seawater intrusion, especially where the aquifer bottom is very deep below the sea level, also far from the coast, and the relevance of the detailed knowledge of the aquifer bottom in supporting any kind of management. [ABSTRACT FROM AUTHOR]

Southern Italy is characterized by important archaeological sites developed during the pre-roman period. Among these, Paestum and Velia Archaeological Park, located in the Campania region, represents one of the most important and well-preserved sites of the Magna Graecia. During the last year, several unexpected archaeological findings have permitted the supposition of the presence of another undiscovered temple at Paestum, in a not yet investigated area of the site, close to the fortification walls (Western City Walls) of the ancient city and a few meters away from the gate of Porta Marina. To support this amazing hypothesis, the Paestum and Velia Archaeological Park and the National Research Council planned an accurate campaign of geophysical surveys, based on the combined use of Geomagnetic and Ground Penetrating Radar methodologies. The results of the geophysical surveys have effectively supported the detection of the temple, providing detailed information about its location and highlighting the geometry of the basement of the structure with high accuracy. The discovery sheds new light on the archaeological and architectonic history of the site and may represent one of the most relevant archaeological discoveries of the XXI century performed in Italy. [ABSTRACT FROM AUTHOR]

Detection and monitoring of underwater structures is one of the most challenging applicative scenarios for remote sensing diagnostic techniques, among which ground penetrating radar (GPR). With this aim, an imaging strategy belonging to the family of microwave tomographic approaches is proposed herein. This strategy allows the imaging of objects located into a wet sand medium below a freshwater layer and it can find application in investigation of lakes, rivers, and hydraulic structures. The proposed strategy accounts for the layered structure of the scenario under test by exploiting a spatially variable equivalent permittivity in the inverse scattering model. This allows a reliable reconstruction of depth and horizontal size of underwater hidden objects. The imaging capabilities of the strategy are verified by processing experimental data referred to a laboratory environment reproducing a submerged archeological site at scale 1:1. The results are compared with those obtained by modelling the reference scenario as a homogeneous medium, in order to verify the effective improvement in terms of reconstruction accuracy. [ABSTRACT FROM AUTHOR]

The ISTIMES project, funded by the European Commission in the frame of a joint Call "ICT and Security" of the Seventh Framework Programme, is presented and preliminary research results are discussed. The main objective of the ISTIMES project is to design, assess and promote an Information and Communication Technologies (ICT)-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring of critical transport infrastructures. The integration of electromagnetic technologies with new ICT information and telecommunications systems enables remotely controlled monitoring and surveillance and real time data imaging of the critical transport infrastructures. The project exploits different non-invasive imaging technologies based on electromagnetic sensing (optic fiber sensors, Synthetic Aperture Radar satellite platform based, hyperspectral spectroscopy, Infrared thermography, Ground Penetrating Radar-, low-frequency geophysical techniques, Ground based systems for displacement monitoring). In this paper, we show the preliminary results arising from the GPR and infrared thermographic measurements carried out on the Musmeci bridge in Potenza, located in a highly seismic area of the Apennine chain (Southern Italy) and representing one of the test beds of the project.