A geophysical exploration employing ground‐penetrating radar (GPR) and electrical resistivity tomography (ERT) was conducted at the Western Cemetery, Giza, Egypt, in 2021–23 by a joint research team of Higashi Nippon International University, Tohoku University and the National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Egypt. We believe we found an anomaly: a combination of a shallow structure connected to a deeper structure. The shallow structure, which is L‐shaped in the horizontal plane, 10 m by 10 m, was clearly imaged by GPR. It seems to have been filled with sand, which means it was backfilled after it was constructed. It may have been an entrance to the deeper structure. Its depth is of up to 2 m, measured from the ground surface. Below this structure, ERT reveals a highly electrically resistive anomaly, which extends over an area of about 10 m by 10 m. The depth of the structure is about 5–10 m below the surface. Electrically resistive material in a sand dune can be a mixture of sand and gravel, including sparse spacing or air voids within it. Neither GPR nor ERT could identify the properties of the anomaly.

This paper deals with the possibilities of ground-penetrating radar (GPR)-based quality control testing, which was demonstrated on an experimental road section of a ~220–240 m long Hungarian residential street. The measurements and their assessment aimed to control the prescribed compactness and air void content of newly built asphalt layers. Research has discussed the relationship between the air void content and the dielectric constant of asphalt layers, and provided empirical results for this relationship. We suggest a new logistic model with lower and upper asymptotes instead of the exponential formula often used in the literature. Contrary to this newly developed robust model, existing models are sensitive to extreme dielectric constant values due to the mathematical nature of their exponential function. The results of the new logistic model are compared to those of the Hoegh–Dai (HD) and Minnesota Department of Transportation (MnDOT) models on the basis of a few calibration data points. Through systematic data collection and analysis, the developed robust empirical model demonstrates a significant correlation between the relative permittivity and air void content in asphalt mixes, enabling accurate estimation of the air void content within a ±0.5% margin of error. The air void content can be applied to estimate the asphalt layer modulus. The developed model can be further exploited by utilizing a combination of GPR and drone technology. The “symbiosis” of these technologies can lead to a totally non-destructive imaging system, which can then be applied to environmental monitoring of roads and their surroundings in terms of quality control of asphalt compaction work and the hot asphalt mix behind the compaction roller during pavement construction.

This study evaluates the impact of seepage on the integrity of artificial levees in low-lying regions, with a particular focus on Hungary, where levees built over a century ago lack comprehensive construction documentation, complicating current assessments of their effectiveness. Advanced geophysical methods – electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) – were applied in a controlled tank experiment designed to simulate varied flood conditions along a 37-m levee section. The three-dimensional (3D) ERT profiles successfully delineated seepage pathways as the tank filled, while the 3D GPR profiles indicated areas of increased amplitude, corresponding to seepage zones and the water table. Validation through drilling confirmed the geophysical findings, underscoring the accuracy of ERT and GPR in non-destructively identifying subsurface features and seepage channels. The results highlight the applicability of these methods for evaluating levee integrity and seepage dynamics, offering a reliable approach for flood risk assessment in Hungary and similar flood-prone areas worldwide.

The quality of newly constructed pavement depends mostly on compaction, which is essential for ensuring the pavement’s longevity and performance. Traditional methods of evaluating pavement compaction and density, such as core sampling and nuclear gauge measurements, are often time-consuming and invasive and provide only a limited amount of data at a low spatial resolution on the potential air void content of the asphalt layers. The present study aimed to assess the specific gravity (G_mb) of a dolomitic asphalt mixture at different degrees of compaction using GPR techniques. Relative density (RD) maps were generated to visualize the spatial homogeneity of the asphalt density. Nuclear density gauging was applied for the calibration, and cores were used to validate the results. The survey was conducted on two recently paved roads in Szeged, Hungary. After testing various approaches, it was found that applying horn antennas and the surface reflection (SR) method is the most feasible way to obtain reliable and accurate dielectric permittivity (ε) data. Based on the measurements, clear relationships were found between dielectric constants, G_mb, and aggregate size. The findings highlight that it is possible to indirectly determine the G_mb of asphalts composed of dolomite and limestone aggregates using GPR, with aggregate sizes ranging from 11 mm to 25 mm and G_mb values between 2.43 and 2.57 g/cm³. Consequently, a robust function was developed, which can be applied to other asphalts with similar compositions.

Geological structures are the most critical parameter for understanding the distribution of groundwater, oil, and minerals. In Siwa Oasis and other oases with comparable geological settings in the northern Western Desert, Egypt, brackish groundwater seeps to the surface through fractures and permeable zones, sustaining phreatophytic vegetation and enabling human habitation in otherwise arid environments. The formation of these oases is closely tied to the subsurface structural and hydrogeological conditions. To determine the origin of these lakes, a geophysical investigation was conducted using magnetic and magnetotelluric (MT) data to identify whether the water leakage stems from deeper artesian aquifers or shallower marine-origin reserves. Magnetic data were used for the geological structural analysis and the depth estimation of basement rocks. The Magnetic Data Analysis includes constructing the Total Horizontal Gradient (THG), Tilt Derivative (TDR), and 2D Magnetic Modelling Constrained by borehole data to estimate basement depths. Magnetotelluric (MT) data analysis includes obtaining 3d resistivity models via inversion, and Cross-sections were extracted to trace fault zones and lithological contrasts. The Key Findings from this study are Surface Lineaments that are dominant in the Northeast (NE), North (N), and East–Northeast (ENE), with a minor East–West (E–W) trend. Shallow Trend Analysis (Tilt Derivative—TDR): Revealed structures in NE-SW, NW–SE, and E–W directions. Total Horizontal Gradient (THG) Map: Confirmed major structural trends in NE–SW, NW–SE, and E–W directions, with additional W–NW trends. The E–W trend correlates with most lakes in the study area. Depth estimation (2D magnetic modelling): Basement rock depths range between 3400 and 4600 m in the magnetic data coverage. The magnetotelluric (MT) model reveals a near-surface E-W direction with resistivity variations linked to lithology changes and groundwater presence.