The effect of wavenumber filtering on synthetic two-dimensional magnetotelluric data

The magnetotelluric (MT) method, an electromagnetic sounding technique used in geophysical exploration, is considered. The MT method is based upon the measurement of the naturally occurring electromagnetic field at the surface of the Earth and the interpretation of the surface electromagnetic field to infer subsurface structure. When the region of the Earth being surveyed by the MT method has strong lateral heterogeneities, information about the deep structure of the Earth is obscured by near surface features, leading to significant interpretational problems. A low-pass wavenumber filtering method used to deal with this problem is described and evaluated by comparing the calculated apparent resistivity of a model of the Earth consisting of a two-dimensional heterogeneous layer on the surface of a horizontally stratified Earth with the wavenumber filtered apparent resistivity. Its effectiveness is confirmed.<>