A simple function for mapping induced currents

A linear inverse method that can be applied to the spatial structure of vertical fields has recently been presented. The application of the method to a regional geomagnetic dataset provided bounds on the lateral and vertical distribution of current concentrations, over a known anomaly. The results obtained by this rigorous analysis are compared with the results that can be obtained using a simple mapping function. The function is the anomalous vertical to anomalous horizontal field-ratio. The high degree of correspondence between the two sets of results confirms that the ratio is a useful, quantitative function for mapping geoelectric boundaries.