西南地区强震活动的群体特征

GROUP FEATURES OF STRONG EARTHQUAKE IN SOUTH-WEST REGION

本文从西南地区１９００年以来Ｍ≥６．０级强震资料出发，对强震活动的群体特征进行了探讨。结果表明，西南地区强震活动呈现出明显的群体特征，在时间分布上表现为活跃期与平静期相交替的周期性，在活跃期Ｍ≥６．０级地震活动的丛集特征显著，并且符合非线性加速发展过程。在空间分布上强震活动在活跃期表现为具有主体活动地区、群体迁移、由局部区域向整体地区发展等特征。根据这些研究结果分析认为，西南地区自１９８８年开始的最近一个强震活跃期尚未结束，在今后几年还可能会发生几次６级强震，并有发生７级大震的危险性。

Group features of strong earthquakes in South-west region are explored in this paper from the data of M≥6 since 1900.The results show that the group features of strong earthquakes in South-west region are clearly demonstrated which have alternative active and quiescent periods.Cluster features of M≥6 are notable during the active period and consistent with non-linear acceleratioon process.The features with major active region,group migrations,and developing from local to overall are also shown up in spatial distribution.Accoring to the above results we consider that the active period of strong earthquakes beginning from 1988 has not been ended,and there will happen several M=6 earthquakes and risk of M=7 in the following years.