Long Temporal Variation of Seismic Parameters for Seismic Patterns Identification in Greece

Abstract

A new approach of detailed spatio-temporal variation analysis of seismic data is proposed by means of FastBEE (Fast estimation of Big Expected Earthquake) aiming at the regional monitoring of seismic activity for premonitory seismic patterns identification.For the investigation of temporal variation, a set of seismic parameters is used, like the logarithm of the number of earthquakes logN, estimates of 6-value obtained by the maximum likelihood estimation model, time clustering of seismic activity AR(t) and of energy released E M , since they can be considered as precursory seismological indicators. Earthquake catalog data, used in this approach, were elaborated in order to construct the time series for each parameter within a time window, large enough, as to guarantee statistical meaningful result.The Hellenic trench-arc region under investigation is chosen in the basis of its seismotectonic characteristics, in relation to the spatial extent of the seismogenic zone.The tools were tested, for long temporal variation features in the Ionian Islands Sea and the North Aegean Sea regions and its successful applicability is presented. The rise of irregularity, along these temporal profiles, was formulated in specific quantitative premonitory seismic pattern. In most of the cases, FastBEE premonitory pattern found shows significant changes from the background values of each parameter. Parameter logN shows a valley form curve, which start to increase before the expected earthquake occurrence, as well as the energy parameter E 273 , while b-value temporal estimates are forming a mountain shape curve, before the occurrence of a big earthquake. Instead, parameter ÙR(t) present a rapid fluctuation, without any kind of premonitory character 1

Recent 2005-2006 strong seismic activity in Greece under the aspect of seismicity parameters temporal variation analysis

“…Temporal variations of b-value have been detected prior to major earthquakes in Japan and Greece, (Imoto 1991, Baskoutas et al 2004. On the other hand the number of earthquakes and the rate of energy released in space and time introduce the measure of seismicity in certain areas.…”

Space Regularity Manifestation of the Temporal Variation of Seismic Parameters: Possibility for the Strong Seismic Activity Assessment

“…Seismicity parameters and their time and space analysis is a very common approach (Habermann and Wyss, 1984;Papadopoulos and Voidomatis, 1987;Bowman et al, 1998;Bowman and King, 2001;Bowman and Sammis, 2004;Papazachos, 2000;Wiemer, 2001;Papadopoulos et al, 2004), to investigate geodynamic regime in seismic active regions. Significant changes of the seismicity rate have been reported in several areas of the world (Wiemer and Wyss, 2002;Enescu and Ito, 2003;Baskoutas et al, 2007).…”

Qualitative precursory pattern before several strong earthquakes in Greece.

“…In the overwhelming majority, the study of these precursory patterns were based mainly on the statistical analysis or the spatiotemporal characteristics of the seismicity (Habermann, 1981;Kanamori H., 1981;Caputo et. al., 1983;Papadimitriou and Papazachos 1985;Matthews and Reasenberg, 1988;Eneva and Hamburger, 1989;Shaw, et al, 1992;Romanowicz, 1993;Kossobokov and Carlson, 1995;Press and Allen, 1995;Shebalin et al, 2000;Di Giovambatista and Tyupkin, 2000;KeilisBorok, et al, 2002;Papadopoulos et al, 2002;Tiampo et al;Papadopoulos et al, 2003;Zavyalov, 2003;Papazachos et al, 2004;Baskoutas et al, 2004;Matsumura, 2006;Sobiesiak, et al, 2007;Papadimitriou P., 2008).…”

“…The analysis tool, in this algorithm, was designed to obtain temporal variation profiles of some basic seismicity parameters, by the elaboration of common earthquake catalogue data. The retrospective application of this algorithm (Baskoutas et al, 2004;Baskoutas et al, 2011;Papadopoulos and Baskoutas, 2011) has shown that the obtained temporal variation profiles, over a long time interval, present a clear precursory regularity, which can be related to strong earthquake occurrence. This behaviour, introducing a new model regarding the intermediate term earthquake prediction, was interpreted (Papadopoulos and Baskoutas 2011) in term of the phases of the phenomelogical «Consolidation Model" of the earthquake preparation process, proposed by Dobrovolski (1991).…”