Spectral Analysis of MT Data Measured at the Tucuman Basin

During 1990 a magnetotelluric survey have been performed in the Tucuman basin at the north-east of Argentina. Spectral analysis of data in the interval 0.1-200 sec have been made using the conventional periodogram method. Though a good estimation has been achieved, the errors were in some cases important. To determinate if this kind of analysis may be improved we have adapted a robust processing method to the selected range of frequencies and the resulting spectra were compared with the ones previously obtained.