A model study of telluric fields in two-dimensional structures

Summary. In recent years telluric sounding has been replaced by MT (magnetotellurics). However, several new purely telluric parameters, besides the traditional Jacobian, have been shown to be efficient geophysical indicators of lateral conductivity variations. A set of typical two-dimensional structures is analysed to demonstrate the resolving power of the new indicators. For such telluric studies, a wide frequency band is a great asset, especially because the indicators are best displayed as pseudo-sections in the frequency domain. However, a wide frequency range is easily achieved when only the telluric field needs to be measured. In MT the magnetic sensing coils often severely reduce the available bandwidth.