**1. Introduction**

The measurements and analysis of the variation in gravity over the Earth's surface have become powerful techniques in the investigation of the subsurface structures at various depths [1]. Where the gravity anomaly is often attributed to the lateral variation in density-contrast and therefore, one of its major applications, being is used as a reconnaissance tool for and mapping the basement rock's morphology, and its depth below the sedimentary covering of basins. The most challenging problem of ambiguity, for interpreting the potential-field data (gravity and/ or magnetic), is still facing the researchers, where the modeling of potential-field data is a non-linear problem. In general, the reference body or source body (i.e., causative body) is imported into the potential model (gravity and/or magnetic), as the initial approximation of the anomaly source, and its parameters are obtained from available geological and geophysical information [2]. Ambiguity in gravity

interpretation is inevitable because of the fundamental incompleteness of real observations; it is, however, possible to provide rigorous limits on possible solutions even with incomplete data [3]. Since a unique solution cannot, in general, be recovered from a set of field measurements, geophysical interpretation is concerned either to determine properties of the subsurface that all possible solutions share or to introduce assumptions to restrict the number of admissible solutions [4].

However, a unique solution may be found, when assigning a simple geometrical shape to the causative body [5]. Also, a unique solution can be found by an attempt for treating the problem of ambiguity with a new vision for analysis of the corrected acquired data (measurements) and related it analytically, logically, or mathematically, to its causative sources, as an attempt of the present research.

The newly proposed method is an attempt to reveal and trace the concealed subsurface geological formations' thicknesses and basement depth at each point of the profile (s), of the Bouguer gravity anomaly map, relatively to the formations' thicknesses and basement' rock depth of a prior known in controlling point (e.g., borehole data). Fortunately, almost most of the geological structures can be approximated, by one or more of the available simple geometrical shape models, to represent the causative sources for gravity anomalies. There are several gravity forward techniques to estimate the depth to basement based on rather different approaches that have been proposed before by many authors, such as [6–9]. The forward modeling of mass distribution is a powerful tool to visualize Free Air and Bouguer gravity anomalies that result from different geological situations [10].
