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Nomikos, C.
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- PublicationOpen AccessThe spectrum of thermally stimulated currents in rock samples from KTB drilling: preliminary results(2001-04)
; ; ; ; ; ;Anastasiadis, C.; Technological Educational Institution of Athens, Greece ;Triantis, D.; Technological Educational Institution of Athens, Greece ;Vallianatos, F.; Technological Educational Institution of Crete, Greece ;Nover, G.; Mineralogisches Institut der Universitat Bonn, Germany ;Nomicos, C.; Technological Educational Institution of Athens, Greece; ; ; ; The technique of thermally stimulated depolarization currents (TSDC) was applied to fine grained amphibolite rock samples extracted from KTB drilling. Each sample was cooled down to liquid nitrogen temperature and consequently heated at a constant rate b = 4 K/min while at the same time it was shorted by a sensitive electrometer. Thermocurrent glow curves were detected in the range from 180 to 360 K. By applying the TSDC method, an effort was made to carry out a preliminary analysis of the TSDC spectrum.163 165 - PublicationOpen AccessInvestigating 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)(2000-04)
; ; ; ; ;Colangelo, G.; Centro di Geodinamica, Università della Basilicata, Potenza, Italy ;Lapenna, V.; Istituto di Metodologie Avanzate di Analisi Ambientale, CNR, Tito, Italy ;Vallianatos, F.; Technological Educational Institute of Crete, Greece ;Nomikos, C.; Technological Educational Institute of Athens, Greece; ; ; 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.190 217 - PublicationOpen AccessThe latest aspects of telluric and electromagnetic variations associated with shallow and intermediate depth earthquakes in the South Aegean(1997-03)
; ; ; ; ; ;Nomikos, K.; Technical Educational Institute of Athens, Athens, Greece ;Vallianatos, F.; Technological Educational Institute of Crete, Chania, Crete, Greece ;Kaliakatsos, I.; Technological Educational Institute of Crete, Chania, Crete, Greece ;Sideris, E.; Technological Educational Institute of Crete, Chania, Crete, Greece ;Bakatsakis, M.; Technological Educational Institute of Crete, Chania, Crete, Greece; ; ; ; Recent observations of telluric and electromagnetic field variations (radioemissions) assocuated with shallow and intermediate depth earthquakes in the South Aegean are presented. A telemetric system, installed on Crete Island, which continuously records the telluric and electromagnetic field variations is described. In the field stations of the system we measure both the telluric variations (using an appropriate electric dipole configuration) and the horizontal electric component of the electromagnetic field in 3 kHz, 10 hKz, 41 MHz and 53 MHz (using tuned and l/2 antennas respectively. Furthermore, a theoretical model is given on the generation and the form of preseismic telluric variations based on the charge dislocation model.208 367