Inversion of broad frequency band geomagnetic response data.

Abstract

Electromagnetic response data for the Earth covering a wide frequency span are analysed using linearised inverse theory. The response measure adopted is the natural logarithm of the complex apparent resistivity. Model finding and interpretation takes place in plane geometry, a simple transformation converts the solutions to spherical geometry for global problems. Thus the methods will apply to local problems, where the combination of AMT and MT data provides several decades of frequency, and to global problems of which this paper is an example. The global data used here are drawn from four sources and cover more than 6 decades in frequency (3.5×10-9 to 8.7×10-3Hz).