Temporal and spatial variations of scaling behavior of seismic process in Caucasus

In the present research we investigate variation of scaling features of earthquakes' temporal and spatial distribution in Caucasus from 1960 to 2014. Data sets of waiting times and inter-earthquakes distances were obtained from the original and declustered Caucasus catalogues. For the assessment of long-range time-correlations of used data sets the method of Detrended Fluctuation Analysis(DFA) was used. We analyzed dynamical features of seismicity in Caucasus by assessing scaling characteristics of earthquakes' time and space distribution for shorter time periods and calculated DFA slopes for different sliding windows. Exactly, calculations were carried out for sliding windows of 500 data length. DFA scaling exponents variations of waiting time sequences obtained from the original and declustered catalogues were assessed by different order of polynomial fitting. In addition to fixed length data sets, the scaling exponents were separately calculated for 5 years long sliding windows. The data of surrogate waiting times obtained by shuffling of original series were processed also by DFA method. It was found that scaling exponents calculated for different windows vary in a wide range indicating variable temporal behavior from anti-persistent to persistent type. Different DFA scaling regimes are observed. Close to 0.5 and antipersistent scaling exponents were obtained for the time periods when the strongest regional earthquakes occurred. In the present work, we studied dependence of scaling properties of waiting times series and distances between consecutive earthquakes in the catalogue of Caucasus in different released energy range. We tested our results for scaling exponents calculated for different length of sliding windows. (author)