Etude sismo-gravimétrique et implications structurales et hydrogéologiques de la plaine de Medjerda (NW Tunisien)

Abstract

The Medjerda plain is endowed with a gigantic multilayer aquifer system enclosed in quaternary alluvium, fed by Medjerda Wadi and its tributaries.Through multidisciplinary approaches based on the compilation of geological studies (fracturing analysis, geological sections ...) and geophysical imaging techniques (gravity and 2D seismic reflection) that will allow the characterization of aquifer formations in the Medjerda plain (Northwest Tunisia). In order to evaluate the subsurface spatial variation, the geological formations, the hydrogeological potential, as well as the degree of fracturing and their role in aquifer recharge processes. The results of the gravimetric analysis highlight the positive and negative anomalies, accurate to the heterogeneities of the subsoil. Different types of gravity treatments are used to map geological contacts, faults and their spatial characteristics (horizontal gradient coupled with upward extension and Euler deconvolution). As for the seismic results, these are in the form of 2D seismic profiles, processed with gain filtering sequences, to highlight sedimentary interfaces that separate the sedimentary layers, provide information on the deposit mode of strata and possibly on subsequent events (discrepancies, lithostratigraphic truncation ...).