Characteristics of seismicity evolution revealed by algorithmic complexity

On the basis of nonlinear dynamic theory and by using algorithmic complexity to analyse the characteristics of time sequence in non-linear dynamics, the law of seismicity and the dynamic characteristics that form the complex phenomenon of seismicity are studied in this paper. The earthquake magnitude algorithmic complexity, AC - values, and the earthquake temporal algorithmic complexity, T AC-values, are introduced. Through selecting the strong earthquakes with Ms �� 6.0 in Eastern China and those with >6.5 in Western China since 1970, a posterior analysis of AC-values and T AC-values has been made; and based on the perspective seismic gaps in the greater North China region during 1970 to 1987, as a background, a perspective test and analysis of AC-values and T AC-values have been made, and analysis of the stability and reliability of AC-value and T AC-values are conducted. The results show that the algorithmic complexity decreases with time before the main shocks. It indicates that, with the variations of the earthquake source parameters and various physical properties of crustal medium, the space-time distribution of moderately small earthquakes shows an obvious variation, which is from the original disorder and chaotic state to some ordered one.