Interpretation of magnetic data using an enhanced local wavenumber (ELW) method

Abstract

This paper presents an enhancement of the local-wavenumber method (named ELW for “enhanced local wavenumber”) for interpretation of profile magnetic data. This method uses the traditional and phase-rotated local wavenumbers to produce a linear equation as a function of the model parameters. The equation can be solved to determine the horizontal location and depth of a 2D magnetic body without specifying a priori information about the nature of the sources. Using the obtained source-location parameters, the nature of the source can then be inferred. The method was tested using theoretical simulations with random noise over a dike body. It was able to provide both the location and an index characterizing the nature of the source body. The practical utility of the method is demonstrated using field examples over dikelike bodies from Canada and Egypt.

Interpretation of self-potential anomalies by Enhanced Local Wave number technique

“…In order to develop a model-independent technique, Salem et al (2005) extended the above concept to define a complimentary local wave-number, K z by…”

“…Recently, a model independent technique-called the Enhanced Local Wave number (ELW) has been developed by Salem et al (2005) to interpret the magnetic data over 2D source geometries. By this technique, we can determine the location and the depth with high precision and also estimate the type of the causative source geometry by computing the structural index (SI)-a concept originally developed by Thompson (1982).…”

Global nonlinear optimization for the interpretation of source parameters from total gradient of gravity and magnetic anomalies caused by thin dyke

“…The amplitude of 2-D analytic signal, from the measured magnetic field anomaly for the same example is taken from Srivastava and Agarwal, 2010. The aeromagnetic data was taken over a flight height of 12 m (Salem et al 2005). The anomaly is interpreted using the same approach as discussed earlier.…”

The deep crustal magnetic structure of Britain

“…The associated depth-estimation procedures currently in use (Salem et al, 2005(Salem et al, , 2007 typically assume that the idealised bodies are spatially isolated and locally 2-dimensional and that the contact has an infinite depth extent. The former assumption may have limited applicability in relation to deeper basement sources as may be judged from the example cross-sectional model of Figure 2b.…”