Mahdia groundwater aquifers exploration (Eastern Tunisia, Mediterranean basin) via advanced gravity analysis: hydrogeological implications

Geophysical techniques such as gravity, magnetic and seismic are perfect tools for detecting subsurface structures of local, regional as well as of global scales. In fact, the Mahdia aquifer system (Eastern Tunisia, Mediterranean basin) is economically important with the over exploitation of its shallow aquifers and the marine intrusion. Thus, different gravity treatments and filters were processed. In this case, we used numerous techniques such as regional-residual separation, Tilt Angle and total horizontal gradient. The structures highlighted using the filtering techniques suggest that the Mahdia aquifer system is affected by a major NE-SW fault system. A residual gravity response of the Mahdia aquifer system was rationally isolated. The main structural features were then outlined and depths of rooted sources were detected. The obtained results show that the aquifer is divided into many basins separated by hydro-geologic barriers within the investigated aquifer system. Forward gravity modeling highlighted the Mahdia aquifer system subsurface extent. A geophysical basement topography mapping enhancing the subsurface overview was also yielded. The novel insights gained from this study have significant implications for understanding hydrogeological dynamics and managing water resources in similar regions affected by over-exploitation and marine intrusion.