用算法复杂性分析地震活动演化特征

CHARACTERISTICS OF SEISMICITY EVOLUTION REVEALED BY ALGORITHMIC COMPLEXITY

以非线性动力学理论为依据，用非线性动力学中分析时间序列的算法复杂性研究地震活动规律和构成地震活动复杂现象的动力学特征。提出了按震级计算的地震算法复杂性AC值和按发震时间计算的地震算法复杂性TAC值。选取1970年以来中国东部Ms≥6.0地震，西部Ms≥6．5的强震，对AC值和TAC值进行回顾性分析；利用1970～1980年大华北地区展望性空区识别结果，对AC值和TAC值进行展望性检验分析，并进行了稳定性和可靠性分析。所得结果表明，主震前算法复杂性表现为低值异常变化；表明主震前孕震区震源参数及地壳介质各种物理性质的变化，导致中小地震活动的时空分布出现明显的变化，从原来的无序、杂乱状态向某种有序状态转变。

On the basis of nonlinear dynamic theory and by using the algorithmic complexityto analyse the characteristics of time sequence in non-linear dynamics, the law ofseismicity and the dynamic characteristics that form the complex phenomenon ofseismicity are studied in this paper. The earthquake magnitude algorithmic complexity,AC-values, and the earthquake temporal algorithmic complexity, TAC-values, areintroduced- Through selecting the strong earthquakes with Ms≥6.0 in the Eastern Chinaand those with ≥ 6.5 in the Western China since 1970, a posterior analysis of AC- valuesand TAC-valus has been made, and based on the Perspective seismic gaps in the greaterNorth China region during 1970 to 1987, as a background, a perspective test and ana-lysis of AC -values and TAC-valus have been made, and analysis of the stability and re-liability of AC-value and TAC-valus are conducted. The results show that thealgorithmic complexity decreases with time before the main shocks.It indicates that,with the variations of the earthquake source parameters and various physical propertiesof crustal medium, the space -time distribution of moderately small earthquakes showsan obvious variation, which is from the original disorder and chaotic state to some or-der one.