Y. Contoyiannis

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Fracture in disordered media is a complex problem for which a definitive physical and theoretical treatment is still lacking. We view earthquakes (EQ's) as large-scale fracture phenomena in the Earth's heterogeneous crust. Our main observational tool is the monitoring of the microfractures, which occur in the prefocal area before the final breakup, by(More)
We argue that the fluctuations of the order parameter in a complex system at the critical point can be described in terms of intermittent dynamics of type I. Based on this observation we develop an algorithm to calculate the isothermal critical exponent delta for a "thermal" critical system. We apply successfully our approach to the 3D Ising model. The(More)
We investigate the spontaneous contraction generated by the atria of a frog's heart isolated in a physiological solution. In the relaxation phase, the recorded time series for two different sampling rates possesses an intermittent component similar to the dynamics of the order parameter's fluctuations of a thermal critical system belonging to the mean field(More)
Many aspects of earthquake generation still escape our full understanding. Observations of electromagnetic emissions preceding significant earthquakes provide one of the few cases of premonitory events that are possibly related to a subsequent earthquake. Understanding the factors that control electromagnetic precursors generation seems to be important for(More)
The current fluctuations of a driven resistor-inductor-diode circuit are investigated here looking for signatures of critical behavior monitored by the driving frequency. The experimentally obtained time series of the voltage drop across the resistor (as directly proportional to the current flowing through the circuit) were analyzed by means of the method(More)
In this letter, we show, in terms of the fractureinduced electromagnetic emissions (EME) recorded prior to the earthquake of Chania, Greece [(35.50&#x00B0; N, 23.28&#x00B0; E); October 12, 2013; M<sub>w</sub> = 6.4] and the seismicity of the area, that there were different evidence indicating the advent of the main shock a few days before its occurrence.(More)
A theoretical scheme which relates multiparticle states generated in ultrarelativistic nuclear collisions to a QCD phase transition is considered in the framework of the uni-versality class provided by the 3-D Ising model. Two different evolution scenarios for the QGP system are examined. The statistical mechanics of the critical state is accounted for in(More)
We present a fixed energy sandpile model which, by increasing the initial energy, undergoes, at the level of individual configurations, a discontinuous transition. The model is obtained by modifying the toppling procedure in the Bak-Tang-Wiesenfeld (BTW) [Phys. Rev. Lett. 59, 381 (1987); Phys. Rev. A 38, 364 (1988)] rules: the energy transfer from a(More)