Geothermal Field Research using Gravity and Electric data in Afyonkarahisar Province of Western Turkey

Geothermal is one of the important energy sources because it is renewable energy and does not have any significant damage to the environment. The western Anatolian part of Turkey has a high potential in terms of geothermal energy. The study area, which is thought to have geothermal characteristics, is close to Afyonkarahisar province in Turkey. In this study, gravity data with horizontal gradient magnitude (HGM) and tilt angle map (TAM) techniques, and electric resistivity data with vertical electric sounding (VES) technique are used for the reveal of underground structure and location of hot water regions. Thus, locations with excess geothermal energy can be identified and locations of potential hot water areas can be determined. The possible hot areas are characterized with high density contrast and low resistivity values. According to the calculations made, the depth of the target mass for the geothermal source starts from approximately 300 m and continues up to 1100 m. More reliable and accurate results can be obtained by holistic interpretation of gravity and electrical resistivity methods in a geothermal field.

Assessment of Stability of the Area Near Sinkholes in the Village of Berezniki, Gaginskiy District

The article provides with the results of a comprehensive assessment of the stability of the area near the karst sinkholes at Berezniki, Gaginsky district. The materials of geophysical surveys obtained by the method of vertical electric sounding were interpreted taking into account the karstological drilling data. Weakened zones are outlined along the apparent resistivity sections. Dependence of sounding results on the distance from the nearest sinkhole was analyzed. The intensity of sinkhole formation and the average diameter of the karst sinkhole were calculated

Processing of synthetic data for the treatment of geoelectric information for hydrogeological purposes of the Málaga town, Santander (Colombia)

Málaga town presents a serious problem caused by the insufficient environmental offer of the superficial water resource to supply the dotation corresponding to the needs of the urban area. Although the geographic and geological location generates optimal conditions for the occurrence of groundwater, studies on the existence, location and availability are incomplete and fragmented, and in general, there is no information about the hidryc resource. The main objective of the present paper pretends to build through the applied geophysical prospection Vertical Electric Sounding (VES) and Electrical Resistivity Tomography (ERT) the 2D model of electrical resistivity of the subsurface, from the processing of synthetic data to the treatment of geoelectrical information with hydrogeological purposes. The data acquisition and processing allowed the interpretation, from the geoelectric point of view and the basic analysis of the 1D profiles and the 2D models developed; demonstrating the presence of highly fractured aquifers that can provide the municipal supply in the future; results that establish the first step in the evaluation of Málaga’s water resources

Applications of Aeromagnetic and Electrical Resistivity Data for Mapping Spatial Distribution of Groundwater Potentials of Dutse, Jigawa State, Nigeria

Optimal mapping of groundwater resource is usually accomplished using integrated geophysical survey in which two or more techniques are applied. In this work, spectral analysis of aeromagnetic data was used to map the topography of the magnetic crystalline fresh basement underlying the water bearing aquifer of Dutse, Jigawa State Nigeria. Vertical electric sounding technique was used to detect the spatial distribution of the depths to the top of the aquifer within the same area.  The overall goal of the work is to determine the groundwater potential of the area by mapping the spatial distribution of groundwater availability based on aquifer thickness and basement topography. The aquifer depth was found to be within the range of 5 to 15 m with a mean value of 10 m. The basement was found to be highly undulating having depths ranging from 6 to 69 m with a mean value of 24 m. The existence of isolated deep depressions within the basement which appears to be filled by water bearing sediments was thought to be favorable structures for groundwater accumulation. The spatial distribution of groundwater potential was therefore mapped in a reclassified image of three zones, high, moderate and low. The study therefore provides a vital tool for groundwater exploitation and management strategies.

CONTRIBUTION OF DEEP ELECTRICAL RESISTIVITY TOMOGRAPHY TECHNIQUE TO HYDROGEOLOGICAL STUDIES: CASES FROM AREAS IN KAVALA (NORTH GREECE)

The most common geophysical method widely used in hydrogeological surveys concerning deep investigations (150-300m of depth) is the resistivity method and particularly the Vertical Electric Sounding (VES) using the Schlumberger array. VES interpretations assume 1D geoelectrical structure yet it is obvious that such an interpretation assumption is not valid in many cases where 2D and 3D geological features exist. In such cases the application of geoelectrical techniques which can provide both vertical and lateral information concerning the resistivity variations is required. Techniques such as the electrical resistivity tomography, mostly used for the 2D and 3D geoelectrical mapping of near surface applications can be adapted to be used for larger investigation depths provided that modified equipment (viz. cables) is used. In the present paper, the application of deep electrical resistivity tomography (ERT) techniques is applied. ERT array of 21 electrodes, at a distance of 50 meters between them (total length 1000 meters) has been used in several studied areas located in the prefecture of Kavala (North Greece). In several cases near surface structure has been compared with VLF data. The aim of the survey was to study in detail the geological-hydrogeological structure the area of interest in order to suggest the best location for the construction of hydrowells with the most promising results. The 2D images of the geological structure down to the depth of at least 200 meters allowed the better understanding of the behaviour of layered geological formations, since in several cases resistivity values have been calibrated with data from pre-existing boreholes.

GEOPHYSICAL AND WATER QUALITY INDEX SURVEYS OF GROUNDWATER QUALITY AROUND UGBOR DUMPSITE IN BENIN CITY, EDO STATE, NIGERIA, WEST AFRICA.

This study takes a look into groundwater quality at Ugbor Dumpsite area using water quality index (WQI), 2-Dimensional (2-D) geophysical resistivity tomography and vertical electric sounding (VES).The geophysical resistivity methods employed revealed the depth to aquifer, the geoelectric layers being made up of lateritic topsoil, clayed sand and sand. Along the trasverse line in the third geoelectric layer of lateral distance of 76 m to 100 m is a very low resistivity of 0.9 to 13 m from a depth range o f about 3 to 25 m beneath the surface- indicating contamination. Water samples were collected and analyzed at the same site during the raining season and during the dry season. The value of water quality index during the raining season was 115.92 and during the dry season was 147.43. Since values at both seasons were more than 100, it implies that the water is contaminated to some extent and therefore poor for drinking purpose. The Water Quality Index was established from important analyses of biological and physico-chemical parameters with significant health importance. These values computed for dumpsite area at Ugbor were mostly contributed by the seasonal variations in the concentrations of some parameters, such as, conductivity, total dissolved solids, hardness, alkalinity, chlorides, nitrates, calcium, phosphates, zinc, which showed significant differences (P<0.01 and P<0.05) in seasonal variation.