Evaluation and Delineation of Sulfur Groundwater Leakages Using Electrical Resistivity Techniques in Hit Area, Western Iraq

Abstract

Electrical resistivity methods are one of the powerful methods for the detection and evaluation of shallower geophysical properties. This method was carried out at Hit area, western Iraq, in two stages; the first stage involved the use of 1Dimensional Vertical Electrical Sounding (VES) technique in three stations using Schlumberger array with maximum current electrodes of 50m. The second stage included the employment of two dimension (2D) resistivity imaging technique using dipole-dipole array with a-spacing of 4m and n-factor of 6 in two stations. The 1D survey showed good results in delineating contaminated and clear zones that have high resistivity contrast. Near the main contaminated spring, the 2D resistivity imaging technique was applied in four sections length (100 m) using a dipole-dipole array position coincided with the three points VES. We compared the results of the interpretation of imaging the techniques 2D and VES. We found that the 2D imaging resistivity technique was better than VES survey in determining the distribution of pollution under the surface in the area surveyed. It was also found that the polluted water is located about 5 m below the surface. The largest amount of leakage was found towards the northeast and coincided with the direction of the groundwater movement. Spring water has leaked from outside the region through the Kubaisah area. Most of this water is contained in quaternary deposits and karst gypsum fractures.

Detection of Shallow Cavities Using 3D Resistivity Technique in a Small Site Near Haditha City, Western Iraq

“…this indicates that the region is characterized by a shallow cavity, while is more dangerous for engineering projects. This is consistent with the studies conducted by [2,8,9,25,31] to study the karst phenomena of the areas adjacent to the study area, in terms of the spread and size of caves.…”

“…3-D display of subsurface structural geology data files for a small area within the study area (seven profiles), mapped into a single data file that can be read using the RES3DINV software which tends to be inverted. RES3DINV is a computer software [30] that will automatically determine a 3-D resistivity model below the surface using data obtained from a 3-D electrophoresis image [31,32]. The inversion routine used by the software is based on the smoothly constrained least-squares method [31].…”

“…RES3DINV is a computer software [30] that will automatically determine a 3-D resistivity model below the surface using data obtained from a 3-D electrophoresis image [31,32]. The inversion routine used by the software is based on the smoothly constrained least-squares method [31]. A new application of the least-squares method based on Newton's quasirefinement technique can also be used [30].…”

“…In this software, we can also use the traditional Gauss-Newton method which recalculates the Jacobian matrix of partial derivatives after each iteration [31]. It is much slower than the quasi-Newton method, but in areas with large resistivity contrasts greater than 10:1, it gives slight results.…”

Electrical Resistivity Imaging (ERI) for Identifying Near-surface Bodies at Diyala University site, NE of Iraq

“…The electrical resistivity method is one of the earliest geophysical survey techniques [1]. Electrical surveys can estimate the subsurface resistivity distribution by taking measurements on the ground surface.…”