Gravity, GPR and ERT surveys at Al-Maqam campus of United Arab Emirates University (Al-Ain, UAE)

Abstract

Gravity, Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) surveys were carried out in December 2018 inside Al-Maqam campus of United Arab Emirates University (Al-Ain, UAE) in front of Building E-4, as a pilot project to investigate the area for any future extended construction. The study area was 2500 m2. The gravity survey had 37 gravity stations with spacing of around 10m. Five GPR profiles were taken and ERT surveys were run along two selected profiles. The reduced Bouguer anomaly map after terrain, elevation and topographic corrections shows values ranging from 18.7 mGal to 27.8 mGal. The Bouguer anomalies present high values in western part of the study area and low values in the eastern part. A three-dimension (3D) gravity inversion model was constructed and shows density distribution from ground to 100m depth (below ground level). The 3D gravity inversion model indicates a fault trending NE-SW starting from 15m depth to 45m depth (b.g.l.). The GPR results show layering extending from ground level to 5 m depth (b.g.l.). Below 5m the GPR results show noise that can be explained by saturated media. A nearby water well confirmed this saturated layer (6 – 10m depth). The ERT tomograms supported the existence of the fault seen from gravity. The combination of the three geophysical techniques helped us to understand the subsurface structure beneath the study area before future construction projects.