A grid implementation of the SLUTH algorithm for visualising the depth and structural index of magnetic sources

The SLUTH method requires first-order derivatives at two or more different heights above the ground and can estimate the location and depth of source bodies from magnetic data. Results of this method are independent of a specific model type and can be used to estimate the most appropriate model (structural index). This paper presents a grid implementation of the SLUTH method to visualise both depth and structural index from magnetic anomaly data. The implementation uses the Geosoft GX programming language. The method has been tested using theoretical magnetic gridded data and two methods have been used for estimating depth; the estimate from the width of the imaged feature gives an underestimate and the estimate from the rate of fall off of the field with height gives an overestimate. The practical utility of the algorithm is demonstrated using field data from the Saskatoon area of Canada.

► The SLUTH method can be used to interpret the cause of magnetic bodies.
► The input are grids of the magnetic data and three spatial derivatives.
► These grid are required on a lower and an upper (upward continued) datum.
► The output are grids of the type of source and the depth to the source.
► The method has been tested on synthetic and real data.