One of the main goals of the interpretation of magnetic data is the imaging of the boundaries of subsurface structures. In this study, a new edge detector called improved horizontal tilt angle (impTDX) has been introduced and tested on synthetic and measured magnetic data. The filter exhibits high efficiency not only in detecting the boundaries of the sources, but also in determining magnetic sources from different depth levels. The impTDX filter produces more precise and sharper boundaries, increases the discernibility of neighboring anomalies, has the advantage of avoiding creation of false edges, and is less sensitive to noise compared to other known filters, which minimizes the uncertainty in the data interpretation. The proposed filter has been applied to aeromagnetic data from Sohag, Egypt. It highlighted the subsurface magnetic structures with high resolution where a structural map showing normal faults demarcating the subsurface causative horsts and grabens was constructed. This map confirms that the Nile grabens are of tectonic origin related to the opening of the Red Sea. Our findings indicate that the proposed filter can be considered as a valuable tool in mapping of subsurface magnetic structures.

An assessment of potential groundwater areas in the Ifni basin, located in the western Anti-Atlas range of Morocco, was conducted based on a multicriteria analytical approach that integrated a set of geomorphological and hydroclimatic factors influencing the availability of this resource. This approach involved the use of geographic information systems (GIS) and hierarchical analytical process (AHP) models. Different factors were classified and weighted according to their contribution to and impact on groundwater reserves. Their normalized weights were evaluated using a pairwise comparison matrix. Four classes of potentiality emerged: very high, high, moderate, and low, occupying 15.22%, 20.17%, 30.96%, and 33.65%, respectively, of the basin’s area. A groundwater potential map (GWPA) was validated by comparison with data from 134 existing water points using a receiver operating characteristic (ROC) curve. The AUC was calculated at 80%, indicating the good predictive accuracy of the AHP method. These results will enable water operators to select favorable sites with a high groundwater potential.

The present study was designed to give a clear and comprehensive understanding of the structural situation in the Sohag region and surrounding area by applying several edge detectors to aeromagnetic data. In this research, the International Geomagnetic Reference Field (IGRF) values were removed from the aeromagnetic data and the data obtained were then reduced to the north magnetic pole (RTP). A combination of different edge detectors was applied to determine the boundaries of the magnetic sources. A good correlation was noticed between these techniques, indicating that their integration can contribute to delineating the structural framework of the area. Consequently, a detailed structural map based on the results was constructed. Generally, E-W, N45-60E, and N15-30W directions represent the main tectonic trends in the survey area. The structural map shows the existence of two main basins constituting the most probable places for hydrocarbon accumulation. The results of this study provide structural information that can constitute an invaluable contribution to the gas and oil exploration process in this promising area. They show also that the decision in choosing the location of the drilled boreholes (Balyana-1 and Gerga) was incorrect, as they were drilled in localities within an area of a thin sedimentary cover.

Electrical resistivity tomography (ERT) and ground magnetic surveys were applied to characterize an old uncontrolled landfill in a former exploited sand and gravel quarry in an area to the north-west of the city of Cologne, Germany. The total magnetic field and its vertical gradient were recorded using a proton precession magnetometer to cover an area of about 43,250 m². The magnetic data were transferred to the frequency domain and then reduced to the north magnetic pole. The amplitude of the analytical signal was calculated to define the magnetic materials within and outside the landfill. Eight ERT profiles were constructed based on the results of the magnetic survey using different electrode arrays (Wenner, dipole–dipole, and Schlumberger). In order to increase both data coverage and sensitivity and to decrease uncertainty, a non-conventional mixed array was used. The subsurface resistivity distributions were imaged using the robust (L1-norm) inversion method. The resultant inverted subsurface true resistivity data were presented in the form of 2D cross sections and 3D fence diagram. These non-invasive geophysical tools helped us to portray the covering soil, the spatial limits of the landfill, and the depth of the waste body. We also successfully detected low resistivity zones at deeper depths than expected, which probably be associated with migration pathways of the leachate plumes. The findings of the present study provide valuable information for decision makers with regards to environmental monitoring and assessment.