Estimation of Source Location Using Curvature Analysis

Abstract

A quadratic surface can be fitted to potential-field data within 3×3 windows, which allow us to calculate curvature attributes from its coefficients. Phillips (2007) derived an equation depending on the most negative curvature to obtain the depth and structural index of isolated sources from peak values of special functions. They divided the special functions into two categories: Model-specific special functions (including Horizontal Gradient Magnitude (<em>HGM</em>) and absolute value) and Model-independent special functions (including Local Wavenumber (<em>LW</em>) and Total Gradient (<em>TG</em>)). We used the normalized source strength (<em>NSS</em>) as a new model-independent special function to estimate depth and shape factor of gravity and magnetic sources. It has its peak directly over the potential field sources (even for dipping sources), and is independent of magnetization direction in magnetic cases. Spurious results are removed by applying a threshold on the shape index attribute and the shape factor.<br /> In this study, the method has been applied on noisy and noise-free synthetic models. For depth estimation of complex sources, we first estimated the depth and structural index from local wavenumber special function. Then, it was used as input to <em>TG</em> and <em>NSS</em> special functions. Finally, this method was tested on real data from Safoo Manganese ore, Northwest of Iran.