新疆近期两次地震序列的时间信息维特征

本文以新疆两次中强地震的余震序列为例,探讨地震序列不均勻时间分布的分形特征。对其信息维的测算表明,无标度区范围基本稳定,同一时间段内信息维数随震级下限的升高略有降低;而对相同震级下限的样本群而言,不同时段的信息维数具有一定的差异。通常是强余震活动结束之后的信息维数略高于强余震活动期间的信息维数。这一特点对大震后地震趋势的合理估计具有积极意义。

THE TEMPORAL FRACTAL CHARACTERISTICS OF TWO EARTHQUAKE SEQUENCES OCCURRING IN XINJIANG AREA

Taking the aftershock sequences that occurred in the Xinjiang area as examples, the fractal haracteristics of heterogeneous temporal distribution of earthquake sequences is studied in this paper. The results show that most non-scaling ranges of fractal structure are steady. In the same time period the information dimension shows a slight decrease with raising of the lower threshold of magnitude, For the same lower threshold of magnitude, there are some differences among the values of information dimension of different time periods. Generally the information dimension in the period after all strong aftershocks stopped occurring is a little bigger than that during the active period of strong aftershocks. This feature will be useful for judging of the seismic tendency after a medium-strong earthquake.