## 1 Introduction  
Morocco experiences a semi-arid climate characterized by low and irregular annual rainfall, usually less than 200 mm per year, high temperatures, and evaporation rates exceeding 1000 mm, particularly in the southern regions [1, 2, 3]. This has been exacerbated in recent decades by recurring droughs, resulting in water scarcity and the depletion of many water sources that are critical for the survival of the population [4]. In the Sidi Ifni region of southwest Morocco, households often face water shortages due to the overexplotiation and vulnerability of surface water sources to drought, as well as high rates of evaporation, which exacerbate surface water depletion. Additionally, completed wells in the area have low flow rates and uneven distribution, with 60% showing very low flows (0.5 to 1.2 L/s) and 30% being dehydrated due to the thick geological substratum dominating the area. Most water inflows in these wells coincide with faults or fractures [5; 6; 7; 8]. Given these challenges, a comprehensive understanding of the aquifer system in the Ifni inlier is necessary to improve groundwater recognition and exploitation. The research problem addressed in this study is to enhance the structural understanding of the region to rationalize drilling campaigns. To achieve this, the gravimetric method has been used as an indirect technique for mapping geological structures, even in areas concealed by the sedimentary cover. In the hydrogeological context of the Ifni inlier, these structures play a crucial role in the drainage and storage of groundwater, making their mapping and characterization critical. The Ifni inlier, which provides a window into the Precambrian basement of the Anti-Atlas, is composed of crystalline rocks hosting fissured aquifers, where groundwater is contained in tectonic discontinuities such as faults, fractures, and alluvial depressions. To map the tectonic faults and their influence on groundwater dynamics in the Ifni inlier, indirect geophysical methods are needed due to the presence of a thin Quaternary cover obstructing geological observations and surface data [9; 10; 11; 12; 13; 14; 15]. This study aims to use gravity data analysis to create a detailed map of the fault systems affecting the study area for hydrogeological reconnaissance purposes [11; 12; 13; 14; 15]. The residual gravity data, derived from subtracting the regional anomaly component from the Bouguer anomaly map, is analyzed using different transformation techniques to analyze the gradient of the gravity field [13; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26]. The Horizontal Gradient filter transforms the inflection point of the residual gravity profile into a positive anomaly whose maximum coincides with the fault location, while the Tilt derivative filter is used to confirm the fault position [26; 27; 28; 29; 30]. Finally, the Euler deconvolution is applied to determine the fault depth of rooting [17; 28; 31; 32; 33; 34; 35; 36]. The obtained results are used to establish a comprehensive structural map of the study area, which is analyzed in conjunction with all the available geological, structural, and drilling data to identify areas favorable for groundwater drilling.  
In the sedimentary context, this method can determine the lateral and vertical extent of the basins filling in sedimentary deposits. Additionally, this method facilitates the estimation of water storage capacity within such basins. In the crystalline environment, however, the employment of gravity is primarily focused on the mapping of faults, fractures, and associated weathering effects. These phenomena serve to increase the porosity of rocks and, as a result, enhance their capacity to retain groundwater [9; 22; 24].