الملخص

The present study is a trial to interpret the geophysical data including shallow seismic refraction (SSR), electric resistivity tomography (ERT), and ground penetrating radar (GPR), in the El-Galala area, Northwestern part of the Gulf of Suez, Egypt, in order to delineate its structural inferences, fracture zones in areas in order to help detect and locate any suspected subsurface cavities and to provide appropriate geotechnical seismic factors .The combined results from the interpretation of the ERT and SSR records obtained over the suspected site in the study area could be divided lithologically into three zones, which are the main geological zones based on variation in resistivity and seismic velocities according to competent of bed with slight thickness variation from one profile to another. The first zone is the upper layer of weathered limestone, gravel fragments, and fractured marl, which is distinguished by poor to somewhat good rock quality. The previous layer is overlaid by the second zone, which has a lithology of fractured argillaceous limestone to the competent rock of intermediate quality. The third zone was used as a hardest layer because it contains the toughest layer of limestone and is distinguished by a high level of competent rock. The bedrock at the site has a velocity range is about 1152 to 1230 m/sec for (S-wave) which is related to very compact and hard limestone. All of the GPR profiles reflect the existence of cracks and discontinuity/weak zones, about 2-4 m from the surface level of the area.