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Abstract. Landmines are a type of inexpensive weapons widely used in the pre-conflicted areas in many countries worldwide. The two main types are the metallic and nonmetallic (mostly plastic) landmines. They are most commonly investigated by magnetic, ground penetrating radar (GPR), and metal detector (MD) techniques. These geophysical techniques however have significant limitations in resolving the non-metallic landmines and wherever the host materials are conductive. In this work, the 3-D electric resistivity tomography (ERT) technique is evaluated as an alternative and/or confirmation detection system for both landmine types, which are buried in different soil conditions and at different depths. This can be achieved using the capacitive resistivity imaging system, which does not need direct contact with the ground surface. Synthetic models for each case have been introduced using metallic and non-metallic bodies buried in wet and dry environments. The inversion results using the L 1 norm least-squares optimization method tend to produce robust blocky models of the landmine body. The dipole axial and the dipole equatorial arrays tend to have the most favorable geometry by applying dynamic capacitive electrode and they show significant signal strength for data sets with up to 5% noise. Increasing the burial depth relative to the electrode spacing as well as the noise percentage in the resistivity data is crucial in resolving the landmines at different environments. The landmine with dimension and burial depth of one electrode separation unit is over estimated while the spatial resolutions decrease as the burial depth and noise percentage increase.Correspondence to: M. Metwaly (mmetwaly70@yahoo.com)

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The Nile Delta is one of the oldest known ancient delta, largest and most important depositional complex in the Mediterranean sedimentary basin. Furthermore, it is a unique site in Egypt that is suitable for accumulation and preservation of the Quaternary sediments. In this work we applied time-domain electromagnetic (TEM) method to investigate the Quaternary sediments sequence as well as detecting the groundwater aquifer in the area of study.A suite of 232 TEM sounding at 43 stations were carried out using a ''SIROTEM MK-3" timedomain electromagnetic system. A simple coincident loop configuration, in which the same loop transmits and receives signals, was employed with loop side length of 25 m. The 1-D modeling technique was applied to estimate the depth and the apparent resistivity of the interpreted geoelectrical data.Based on the interpretation of the acquired geophysical data, four geoelectric cross-sections were constructed. These sections show that the Upper Quaternary sequence consists of three geoelectric layers. The Holocene Nile mud is separated into two layers: the agricultural root zone (Layer 1) and thick water saturated mud (Layer 2). The Upper Pleistocene sandy aquifer (Layer 3) is very complicated non-linear boundary. This aquifer is the most important unit since it is considered as the main water bearing unit in the study area.

Saudi Arabia is seeking fresh groundwater resources to face the increase in anthropogenic activities. The groundwater storage variations and occurrence were investigated and the surface and subsurface structures influencing the groundwater resources in the research area were defined using a combined study of Gravity Recovery and Climate Experiment, aeromagnetic data, and electrical resistivity data with other relevant datasets. Results are: The groundwater storage fluctuation is calculated at −0.34 ± 0.01 mm/yr during the period 04/2002-12/2021. The area is receiving an average annual rainfall rate of 117.6 mm during the period 2002 to 2019. Three structural trends, defined in the directions of NS, NNW, and NNE are cutting the sedimentary cover and the basement rocks. The sedimentary cover ranges from 0 to 1.2 km thick. Vertical electrical sounding results indicate three main geoelectric layers: the surface geoelectrical layer of higher resistivity values (428-9626 Ω. m) is made up of unconsolidated Quaternary sediments; the water-bearing layer of saturated sands with a resistivity range between 5.1 and 153 Ω. m and with depths vary from 1 to 94 m, and highly fractured basement rocks with resistivity values ranging from 813 to 6030 Ω. m. The integrated results are useful in providing a comprehensive image of the study area’s surface and subsurface structures, as well as groundwater potential in the southwestern part of Saudi Arabia. Our integrated approach provides a reproducible model for assessing groundwater potential in arid and semiarid areas.

Groundwater is extremely important in a water-scarce country such as Saudi Arabia, where permanent surface water resources are absent. Sustainable and future developments plans are essentially relying on the clear understanding of water resources. To evaluate the water resources in arid countries, the groundwater should be quantified through either traditional or scientifically advanced techniques. Aquifer characteristics, particularly the hydraulic conductivity and transmissivity, are essential for the evaluation the aquifer properties as well as the management and development of groundwater modelling for specific aquifers. The present study aims to evaluate the sub-basaltic alluvial aquifer in the northern part of Harrat Rahat, south of Al-Madinah city, and then estimates the principal aquifer’s hydraulic parameters based on the interpreted 1D resistivity-depth models along the study area. For that, 49 Vertical Electrical Soundings (VES’s) utilizing a Schlumberger electrode array were performed along the southern part of Al-Madinah city. The resistivity of the water-bearing formation, thickness, porosity, hydraulic conductivity, and transmissivity parameters were calculated along the measured longitudinal profile from the interpreted VES data. The estimated porosity, hydraulic conductivity, and transmissivity were achieved along the whole profile with average values of 0.2, 3.5 m/day, and 369.6 m2/day, respectively. The resulting transmissivity values from the VES models were compared with those of previous pumping test measurements carried out in the area and a reasonable correlation between the two data sets was observed. These results indicate that surface geoelectrical resistivity techniques may provide an alternative, rapid, and cost-effective method of estimating the aquifer hydraulic parameters where pumping data is rare or unavailable.