2016年8月24日意大利中部发生M_W6.0地震，2个月之后，震中附近相继发生M_W5.5、M_W5.9、M_W6.5地震。研究这几次较大地震间的相互触发作用及机制十分必要，然而在大地震之后传统地震目录通常缺失很多余震事件，缺失的余震事件包含着早期余震时空分布和迁移规律的信息，为完善余震目录本文利用匹配滤波方法对M_W6.0地震后80天内的连续数据进行余震检测，得到了数十倍于模板数量的新检测事件，检测事件与模板事件组成的新余震目录完备震级为1.0，提高了地震目录的完备性。依据新余震目录进行余震时空分布研究，结果显示M_W6.0、M_W5.9、M_W6.5地震的早期余震迁移规律不同。M_W6.0地震的早期余震沿着断裂走向同时朝两侧迁移；而M_W5.9、M_W6.5地震的早期余震向南、北迁移表示出不对称的特征。通过拟合余震迁移前端发现，M_W6.0、M_W5.5地震的早期余震朝着随后较大地震的方向迁移，且较符合lgt的特征，表明余震迁移可能与慢滑动有关。

An extensional M_W6.0 earthquake struck the Central Italy on August 24,2016. Two months later,three other large shocks-M_W5.5,M_W5.9 and M_W6.5 occurred successively near the focal region of the M_W6.0 earthquake. It is important to figure out the trigger mechanism between these large earthquakes. However, traditional method to detect events usually miss a vast number of aftershocks, which contain the insight of aftershocks distribution and migration. We adopt the matched-filter method to perform the detection of aftershocks through continuous waveforms 80 days after the M_W6.0 mainshock,and the total number of detection events is ten times those listed in the template catalog. Moreover,the magnitude of completeness of the new catalog consisting of both detection and template events is lower than before. Our analysis on new catalog indicates the differences among the evolutions of aftershocks following M_W6.0,M_W5.9 and M_W6.5. M_W6.0 was followed by an aftershock sequence expanding towards both sides along the fault strike,but there were heterogeneous postseismic migrations of M_W5.5 and M_W6.5. Here,we find the early aftershock fronts expand with logarithm time since M_W6.0 and M_W5.5,indicating that the postseismic migration is driven by the aseismic slip.

P315

中国地震科学台阵探测——华北地区东部项目（DQJB17A0105）资助