An iterative approach to depth determination from second moving average residual magnetic anomalies

Abstract EN

We have developed a numerical method to estimate the depth of a buried structure from second moving average residual anomalies obtained from magnetic data using filters of successive graticule spacings.

The problem of depth determination has been transformed into the problem of finding a solution to a nonlinear equation of the form z = f(z).

Formulas have been derived for a dike, horizontal cylinder, geologic contact, and a sphere.

The method involves using simple models convolved with the same second moving average filters as applied to the observed magnetic data.

As a result, our method can be applied not only to residuals but also to observed magnetic data.

The method is applied to synthetic data with and without random errors.

The validity of the method is tested in detail on a field example from Canada.

In all cases examined, the depth obtained gives satisfied results with actual depth.