Detecting differences in temporal distribution of small earthquakes before and after large events
We have evaluated the dynamical properties of the temporal distribution of the small earthquakes. Two main goals of the investigation were: (a) a qualitative evaluation of the nonlinear structure of the time distribution of earthquakes, taking place before and after the strongest Caucasian events; (b) a quantitative discrimination of the dynamics (of time distribution of earthquakes) preceding and following the largest regional earthquakes. The dynamical characteristics of seismicity before and after four recent large earthquakes in the Caucasian region have been investigated. Nonlinear time-series analysis techniques, such as calculation of the correlation dimension for sliding windows and surrogate data analysis tests have been used; inter-event time-interval sequences have been considered as a time series. It was determined that the dynamics of lithospheric processes, generating the temporal distributions of earthquakes, do not change qualitatively before and after the largest Caucasian earthquakes. Inter-event time-interval sequences reveal low-dimensional nonlinear structure in both situations. On the other hand, quantitative analysis shows that the low-dimensional nonlinear structure of the temporal distributions of earthquakes after the largest events is significantly different than those before the largest events.
earthquakes dynamics nonlinear structure time distribution