中国大陆6级地震丛式活动特性分析

ANALYSIS ON CLUSTERING FEATURES OF STRONG EARTHQUAKES IN CHINA MAINLAND

本文从统计学角度研究了自1915年到1989年7月发生在中国大陆的6.0≤M_s≤6.9强震成丛活动的特点。结果表明6级地震丛式活动存在着一定的规律,丛事件连续发生后必有一较长时段其活动较平静,平静过后又进入新的活跃阶段。在地震轮回活动期中,6级地震丛事件在地震动力学系统中具有明显的能量平衡调整和大应变释放补充作用。一般而言,大部分6级地震丛事件之后1.5年内多有7级大震发生,另外采用了方差分析法对未来丛事件进行了预测。我们认为丛事件卷入的强震数目多、持续时间短,对其的研究和预测有可能把握一定时期内地震大形势中的主要地震事件,不失为值得尝试的强震形势分析的途径之一。

This paper statistically studies the clustering feature of strong earthquakes with magnitude 6.0≤MS≤6.9 occurred in China mainland in the period 1901 to July, 1989. Results shwo that there exists a certain reqularity for the clustering activities of such strong earthquakes: after the successive occurrence of clustering events there must be a longer time interval of quiescence and .then a new activity stage begins. In the cycle of seismic activity period, clustering evems of earthquakes with 6≤Ms≤6.9 play obvious roles in energy equilibrium adjustment and strain releasing supplement in the seismic dynamic systems. Generally speaking, after most clustering events of earthquakes (M≥6.0) there would occur a larger earthquake (M≥7.0) in 1.5 year. Additionally, we adopted the variance analysis method to forecast the tendency of the future clusturing events. We suggest that the clustering events include a great number of strong earthquakes in a short duration, so to research and forecast clustering events may probably grasp the main events in the seismic tendency of a certain period. This is ont of the ways for analyzing strong tarththquake tendency.