Fluctuation analysis of the hourly time variability in observational geoelectrical signals

We investigate, by the Detrended Fluctuation Analysis (DFA), the long-range correlations in the hourly time variability of geoelectrical signals measured by the station Tramutola, located in one of the most seismic area of southern Italy. The DFA power-law exponent, characterizing the temporal fluctuations of these signals, shows significant variation, possibly related with the seismic activity of the area investigated.