SUMMARY
Variations detected in geophysical, especially electromagnetic, parameters in seismic active areas have beensometimes attributed to modifications of the stress field. Among the different geophysical methods, magnetotellurics(MT) could be one of the most effective because it allows us to explore down to seismogenic depths. ContinuousMT recording could allow us to evaluate whether possible variations are significantly correlated with theseismic activity of investigated area. To assess the significance of such observations we must be able to say howwell an apparent resistivity curve should be reproduced when measurements are repeated at a later time. To dothis properly it is essential to know that the estimated error bars accurately represent the true uncertainties incomparing the transfer functions. In this work we will show the preliminary results obtained from the analysisof the data coming from the new MT monitoring network installed in Agri Valley. This analysis gives us the possibility:i) to better study the temporal stability of the signals, ii) to better discriminate the noise affecting themeasures by remote reference estimation. The performed analysis disclosed a relatively low degree of noise inthe investigated area, which is a promising condition for monitoring.