Quick imaging of MT data using an approximate inversion algorithm

An approximate inversion method is proposed for the imaging of MT data measured above 2-D geological structures. In discretizing the model parameters a series expansion formula is used with interval-wise constant functions or Chebishev polinomials as basis functions. The expansion coefficients serve as the unknown parameters of the inverse problem. All the data sets collected at various sites along the measurement line are integrated in a single inversion procedure in which the solution of the forward problem is approximated by the well-known 1-D magnetotelluric formulae with the use of the local values (at the measurement site) of the laterally changing model parameters. The imaging method is tested by means of synthetic data set calculated on a 2-D geological model in both TM and TE mode. Our numerical tests show that the proposed imaging procedure gives quick and highly acceptable parameter estimation.