A comparison between spectral and fractal methods in electrotelluric time series

By using electrotelluric time series, that is, data sets of the electric se lf-potential variations in a place close to the Middle American Tectonic Tr ench, we compare two methods of dynamical analysis. First, we calculate the spectral exponent alpha by means of fast Fourier transforms, and on the ot her hand we calculate the fractal dimension D of the time series by using t he so-called Higuchi's algorithm, We find that the second method has remark able advantages over the spectral analysis.