Joint inversion interpretation for gravity and resistivity data: A case study at New Heliopolis City, Cairo, Egypt

Abstract

Gravity and resistivity data were used in the present study for groundwater exploration using a joint inversion process. One hundred fifty three gravity stations and thirty two vertical electrical soundings were used to determine the thickness and resistivity distribution of the different geological units in the study area. Then, the gravity and resistivity data were utilized concurrently to identify the structural elements, stratigraphie units and groundwater potential in the study area. The results of the joint inverse interpretation have strengthened the analysis and consistency of the outcome. The results revealed the presence of four layers. The first is the Quaternary deposits of thickness ranging from 0.5-2 m; the second layer is the Hommath Formation of Middle Miocene age deposits, which have resistivity ranging from 2-3238 ihn and thicknesses ranging from 5-40 m. The third layer is the Gabal Ahmar Formation (Oligocène age), which has resistivity ranging from 5-1148 Hm and a thickness ranging from 10-342 m. The fourth layer is limestone of the Upper Eocene age that exhibits high resistivity values ranging from 80-683ωm, depths ranging from 55-350 m and bulk density 2600 kg/m3. The results also indicate that the area is dissected by different fault elements trending N-S, NE-SW, NE-SW and E-W. © 2010 European Association of Geoscientists & Engineers.