• Economic and Environmental Geology
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• v.27 no.5
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• pp.491-498
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• 1994

The integral equation method is used for magnetotelluric (MT) modeling of a finite inhomogeneity in a two-layered earth. An integral equation relates the incident plane-wave field and the scattering currents in the three-dimensional (3-D) inhomogeneity through the electric tensor Green's function appropriate to a layered earth. This paper describes an effect of overburden and basement on MT responses of 3-D body. The effect of overburden is to reduce the detectability of target, and the reduction of detectability is more apparent for conductive overburden than for resistive one. The effect of basement, on the other hand, may enhance the anomaly due to 3-D body in the upper layer. In case of the resistive basement current perturbations about the body tend to be confined to the more conductive upper layer.