A new approach in the determination of characteristic directions of the geoelectric structure using Mohr circles

The use of Mohr circles into magnetotelluric (MT) intepretation was introdu ced by Lilley (Lilley, 1976). By plotting Z(xx)-rotated versus Z(xy)-rotate d (real and imaginary parts) important information on the conductivity stru cture is obtained. In this paper Mohr circles are employed to reveal the di rections of polarisation of the electric field. Furthermore, the following procedure for Mohr circle analysis is suggested: plotting Z(xx)-rotated ver sus Z(yx)-rotated (instead of Z(xy)-rotated) the principal axes system i.e. , the strike angle, of the regional 2D structure can be resolved in some ca ses. The latter analysis is implemented to MT data from Ioannina area, in N W Greece. Results from other intepretation techniques applied to the same d ataset, such as decomposition methods, tipper and induction arrows analysis , provide support for the validity of the conclusions reached.