Articles | Volume 4, issue 5/6
Nat. Hazards Earth Syst. Sci., 4, 615–631, 2004

Special issue: Precursory phenomena, seismic hazard evaluation and seismo-tectonic...

Nat. Hazards Earth Syst. Sci., 4, 615–631, 2004

  14 Oct 2004

14 Oct 2004

A unified approach of catastrophic events

S. Nikolopoulos1, P. Kapiris2, K. Karamanos3, and K. Eftaxias2 S. Nikolopoulos et al.
  • 1National Technical Univ. Athens, Dept. of Electrical & Computer Engineering Zografou Campus, Zografou 15773, Greece
  • 2Dept. of Solid State Section, Faculty of Physics, Univ. of Athens Panepistimioupolis Zografou, 157 84 Athens, Greece
  • 3Centre for Nonlinear Phenomena and Complex Systems, Univ. Libre de Bruxelles, CP 231, Campus Plaine, B-1050 Brussels, Belgium

Abstract. Although there is an accumulated charge of theoretical, computational, and numerical work, like catastrophe theory, bifurcation theory, stochastic and deterministic chaos theory, there is an important feeling that these matters do not completely cover the physics of real catastrophic events. Recent studies have suggested that a large variety of complex processes, including earthquakes, heartbeats, and neuronal dynamics, exhibits statistical similarities. Here we are studying in terms of complexity and non linear techniques whether isomorphic signatures emerged indicating the transition from the normal state to the both geological and biological shocks. In the last 15 years, the study of Complex Systems has emerged as a recognized field in its own right, although a good definition of what a complex system is, actually is eluded. A basic reason for our interest in complexity is the striking similarity in behaviour close to irreversible phase transitions among systems that are otherwise quite different in nature. It is by now recognized that the pre-seismic electromagnetic time-series contain valuable information about the earthquake preparation process, which cannot be extracted without the use of important computational power, probably in connection with computer Algebra techniques. This paper presents an analysis, the aim of which is to indicate the approach of the global instability in the pre-focal area. Non-linear characteristics are studied by applying two techniques, namely the Correlation Dimension Estimation and the Approximate Entropy. These two non-linear techniques present coherent conclusions, and could cooperate with an independent fractal spectral analysis to provide a detection concerning the emergence of the nucleation phase of the impending catastrophic event. In the context of similar mathematical background, it would be interesting to augment this description of pre-seismic electromagnetic anomalies in order to cover biological crises, namely, epileptic seizure and heart failure.