GEOELECTRIC AND SHALLOW SEISMIC REFRACTION INVESTIGATIONS FOR ASSESSMENT OF THE WATER AQUIFERS IN NORTH RAS MILLAN AREA, SOUTHERN SINAI PENINSULA, EGYPT

Abstract

Ras Millan area, that located West Gulf of Aqaba, acquires its importance recently as one of the groundwater resources in Sinai (Mills & Shata, 1989; Hosney, 1991; and many others). So, the current work aims to delineate the configuration of the groundwater-bearing aquifer and hence evaluating the groundwater potentiality in the area through the application of geoelectric resistivity and shallow seismic refraction methods. A total of 50 vertical electrical soundings and 43 seismic refraction spreads were carried out for this purpose. The resistivity data were interpreted using two 1D software package; Ato program (Zohdy, 1989) and IPI2win (Moscow state, 2001). The shallow seismic refraction data were interpreted using the delay time method, and the resulting depth– velocity models were generated using an advanced finite difference (FD) technique. The combination between the two executed methods indicated that, the subsurface lithology of the area is composed of three subsurface layers overlying the basement. The third layer, which is equivalent to Araba Formation and composes of basal sandstone, is the promising layer as groundwater aquifer. This layer attains 22 m, as average thickness. This thickness decreases generally in the middle parts of the area. The resistivity values of this layer range between 27 and 300 Ω.m, while the velocities range between 3000 and 3400 m/s.