Investigating the time dynamics of geoelectrical signals measured in two seismotectonic environments in the Mediterranean region: the Southern Apennine chain (Southern Italy) and the Hellenic arc (Crete Island, Greece)

Abstract

In this paper we explore the time dynamics of geoelectrical signals measured in two seismic active areas in the Mediterranean region: the Southern Apennine chain (Italy) and the Hellenic arc (Crete Island, Greece). After apreliminary filtering procedure carried out to remove man-made and climatic noises, the geoelectrical time seriesmeasured in both the seismological environments show features that are typical fingerprints of stochastic processes.In particular the time fluctuations follow a dynamics well described by an autoregressive model of a first order(red noise). The model has been tested in the frequency and time domains applying advanced statistical methodologies. Taking into account these results, we propose an objective methodology to pick out from geoelectrical time series anomalous patterns from background noise and we study the possible correlation between the appearance of extreme events in the electrical signals and the local seismic activity. Finally an in dept analysis of results obtained in the two investigated areas has been performed.