利用双差定位方法对2017年2月～2018年5月长岛震群进行重定位,根据重定位结果计算长岛震群地震集中活动区域b值在深度上的变化分布.结果显示:长岛震群重定位的结果主要表现为北、南两个地震活动区域.北部地震活动区域的地震数量多,时间跨度长;南部地震活动区域的地震数量较少,形成时间较晚,震源深度主要集中在地壳深度4～25 km之间;长岛震群北、南两个地震活动区域的b值总体上均随深度增大而减小,在8.5 km深度左右均存在转折上升的情况.长岛震群b值的深度变化特征表明,其应力主要受围岩静压力影响,受断裂活动影响较小.%The Changdao earthquake sequence from February 2017 to May 2018 was relocated by using the double difference location method. According to the result of relocation, the variation of b value with depth in the seismic activity concentrating area in Changdao earthquake sequence is calculated. The results obtained show that the earthquake sequences can be divided into north and south concentrated areas. There is more earthquakes in the northern concentrated area with long time span. The number of earthquakes in the southern concentrated area is relatively small, and the formation time is relatively late. The focal depth is mainly concentrated in the depth between 4 and 25 km. The b values of the north and south concentrated areas decrease with depth. There is an upward trend in depth around 8.5 km. It is inferred that the stress is mainly affected by static pressure of surrounding rock, and the fault activity is less affected.
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