Deemah Saad Mahmoud; Ahmed Ali Madani; Said Mohamed Said; Mohamed Mokhtar Yehia; Tamer Nassar
Abstract
The eastern border of the Nile valley south of Cairo is distinguished by numerous springs and associated surface water bodies, e.g. Ain El-Sira, Helwan, and Atfih. Except the latter, all of them were disseminated in urban areas, and were hardly detected by remote sensing data. Thus, studying the surface ...
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The eastern border of the Nile valley south of Cairo is distinguished by numerous springs and associated surface water bodies, e.g. Ain El-Sira, Helwan, and Atfih. Except the latter, all of them were disseminated in urban areas, and were hardly detected by remote sensing data. Thus, studying the surface water of Atfih spring is key to understanding the nature of the east Nile spring system. Change in this surface water has been detected based on the integration between the spatiotemporal analysis of the multi-spectral satellite images and the Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) rainfall data from 1987 to 2019, and the field investigation. The normalized differential water index analysis reveals an increase in the surface area of the Atfih water body by two to three times during the years 2016-2017. The results clarified the relationship between the appearance of the surface water of Atfih spring and rainfall amounts. Another factor controlling the Atfih water body treated in this work is the geological structures. A field survey aided by the processed satellite data revealed the presence of three fault populations: WNW-ESE, E-W to ENE-WSW, and NNE-SSW. The E-W to ENE-oriented faults are the main faults and have a right-lateral strike-slip sense of movement. This fault pattern and Pliocene shale have a substantial impact on the appearance of the Atfih water body. These faults act as a horizontal channel that allows lateral movement of meteoric water through Eocene carbonate, and water recharge occurs at the highly fractured strike-slip transfer zones.
A. Rezaei; H. Hassani; P. Moarefvand; A. Golmohammadi
Abstract
Ground Penetrating Radar (GPR) is an effective and practical geophysical imaging tool, with a wide set of applications in geological mapping of subsurface information. This research study aims at determination of the geophysical parameter differences in the subsurface geological structures and construction ...
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Ground Penetrating Radar (GPR) is an effective and practical geophysical imaging tool, with a wide set of applications in geological mapping of subsurface information. This research study aims at determination of the geophysical parameter differences in the subsurface geological structures and construction of a 3D fracture model. GPR and resistivity methods were applied to detect the unstable tectonic zones in the C-North deposit. Structural geology investigations were, first, surveyed to detect the faults and fractures in the study area. Based on the structural features, the survey was conducted over an area of 1 km2 with a total of 30 profiles and low-resistivity zones in the C-North deposit which is a great help in reducing their impacts in slope stability studies. GPR sections were, then, obtained from low and high frequency antennas (10 and 50 MHz) to detect fractures and water content zones. The obtained data results demonstrated that the major structural trends in the study area were W–E, NE–SW, and NW–SE while fault zones that can create pathways for groundwater inflow into the deposit in the future. Information obtained from geological and GPR studies were also integrated with drill hole data. The geological information from structures are in good agreement with the actual geological situation. Method and results of this study could be useful in solving problems related to subsurface structures in mining engineering.
