THE EFFECTIVENESS OF THE ELECTRICAL RESISTIVITY TECHNIQUES FOR EXPLORING GROUND WATER OCCURRENCES IN CAVERNOUS LIMESTONE (LABORATORY CASE STUDY) | ||
| Journal of Egyptian Geophysical Society | ||
| Volume 18, Issue 1, 2020, Pages 183-193 PDF (1.78 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jegs.2020.385826 | ||
| Authors | ||
| Sh.M. SALEM1; E.H. SHENDI2; H.M. EZZ EL DEEN1; A.N. EL SAYED1 | ||
| 1(1) Desert Research Centre, Cairo, Egypt. | ||
| 2(2) Faculty of Science, Suez Canal University, Ismailia, Egypt. | ||
| Abstract | ||
| Electrical geophysical techniques, including 1-D vertical electrical sounding (VES); 2-D and 3-D resistivity imaging profiling, have been carried out in the laboratory on a cavernous limestone physical model in order to delineate the effect of the cavities on the measured resistivity values as a preliminary step for a field work in an area covered by cavernous limestone. The dimensions of the used limestone model were 205 cm*205cm*30 cm with a cavity, with dimensions of 30cm*30cm*17 cm, in its center. A number of 77 VES were measured on the limestone model in a grid pattern by using Wenner electrode array starting with a= 5 cm to a= 65 cm. A number of 28 profiles of 2-D resistivity imaging were carried out on the model, covering its middle cavity. 3-D resistivity grid with 42 X 42 electrodes was also carried out on the limestone model. All the above mentioned electrical techniques have been carried out on the limestone model when its middle cavity/cave was completely filled with fresh water, half – filled and empty with few measurements outside the cavity in its four directions. Processing and interpretation of the obtained results, with the above mentioned techniques, showed that the geoelectrical section of the limestone model consists of four layers (A, B, C and D) when the cavity/cave was half filled with fresh water, three layers (A, C and D) when it was completely filled with water and when it was empty, two layers (A and D) only when the measurements were done outside the cavity. These results confirmed the importance of the different geoelectrical techniques in delineating the water conditions of caves and cavities in cavernous limestone and could be applied successfully in the Egyptian deserts, covered by this kind of limestone. | ||
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