Using Euler Homogeneity Equation in Depth Estimation of potential Field Anomalies

    In this paper, we introduce a method for estimating the structural index. This method is used from analytic signal, a function in which defines as energy envelope of the three Cartesian gradients. The efficiency of this method was tested using a synthetic sphere model in 500 m depth.also the applicability of the Euler method was demonstrated on various synthetic models such as prism, dipping dike and vertical cylinder. The results have broad correlation with the assumed parameters used in constructing the models. Findings further showed that if the Euler method would be used correctly, it is able to determine the body regions. In other words, this method produces reasonable results about depth to top of the bodies on the boundaries of the subsurface body. The results of the depth estimation were plotted on a magnetic map by employing the circles with proportional diameter to the estimated depths. The Euler method was tested on real magnetic data from a ground magnetic surveying in North of Iran (Semnan province). In this region, 28 magnetic profiles with 300 m length an N-S direction were acquired. The profile spacing was selected equal to 20m based on the geological and field conditions. The dominant magnetic minerals are Magnetit and Hematit, in which in some portions are altered. The magnetic data was collected using Proton magnetometer model GM19. As the causative body geometry is unknown in this region, then we used from the combination of the analytic signal and Euler in order to estimate the structural index. The estimated value for the structural index was  ,which can be dedicated to thin dike body. Further, we run the Euler method for estimating   the depth to top of the causative body using the estimated structural index. The Euler method determined the depth to top of the body in the studied area as 15-35m