A new multiscale imaging method for estimating the depth and structural index of a magnetic source

Abstract

The fast automatic technique for determining the source parameter is commonly used to interpret magnetic data. A new method is proposed to estimate the magnetic source parameter based on the any-order analytic signals of magnetic anomalies at different altitudes. The new method is based on the relationship between the location, depth, and structural index of the source and the expressions of analytic signals and uses the altitude z and a depth scaling factor [Formula: see text] to establish a new multiscale imaging method called variable depth mirror imaging (VDMI), whose extreme points are related to the source parameters. Two equations are given to calculate the source depth and structural index on the basis of the vertical positions of the peaks of the VDMI sections with two different [Formula: see text]. Moreover, a series of solutions of the source parameters will be obtained when a number of [Formula: see text] is selected, which can make the results more reasonable. The method is stable and can be directly applied to noisy anomalies or high-order derivatives because it is based on magnetic anomalies of upward continuation. In addition, the method is flexible, as we can select different [Formula: see text] as desired. Moreover, the method can be applied to multisource cases and can simultaneously estimate the depth and structural index for each source. The method is tested on noise-free and noise-corrupted synthetic magnetic anomalies. In all cases, the VDMI method effectively estimates the depths and structural indices of the sources. The VDMI method is also applied to real aeromagnetic data from the Hamrawein area, Egypt, and ground magnetic data over the Neibei Farm of Heilongjiang Province, China.