芦山两次强震序列活动特征及余震预测效能对比分析  

Comparative Analysis of the Activity Characteristics and the Aftershock Forecasting Efficiency of Two Earthquake Sequences in Lushan

作　　者：毕金孟 宋程 马永 BI Jinmeng;SONG Cheng;MA Yong(Tianjin Earthquake Agency,Tianjin 300201,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]天津市地震局,天津300201 [2]中国地震局地球物理研究所,北京100081

出　　处：《地震研究》2023年第2期204-215,共12页Journal of Seismological Research

基　　金：地震预测开放基金(XH23072D);中国地震局震情跟踪定向工作任务(2022010116,2020010104)。

摘　　要：利用可充分考虑小震信息的Omi-R-J模型,对2013年芦山M_(S)7.0地震和2022年芦山M_(S)6.1地震序列活动特征进行对比分析,发现芦山M_(S)7.0地震序列较芦山M_(S)6.1地震序列完备性随时间变化更加明显,震后早期检测能力较低,两次地震序列稳定时段检测得到的完整性震级均为1.8级左右。芦山两次地震序列p值差异较小,展示了相对正常的衰减过程;芦山M_(S)7.0地震序列k值明显大于芦山M_(S)6.1地震序列,这或许与芦山M_(S)7.0地震较为发育的余震或强余震有关;芦山M_(S)7.0地震序列b值小于芦山M_(S)6.1地震序列,表明M_(S)7.0地震之后芦山地区仍处于较高的应力状态,而M_(S)6.1地震之后应力处于相对较低的水平。利用N-test方法开展效能评估,结果显示,两次地震序列初期阶段余震发生率展示了较好的预测效能,基于震后初期1天内的数据开展的未来1天的余震预测中,仅有1次预测失效,而在对未来3 d的余震预测中,不存在预测失效的情况。We used the Omi-R-J model,which can fully make use of the information of small earthquakes,to compare and analyze the characteristics of the activity of two strong-earthquake sequences in Lushan,Sichuan Province.we found that the completeness of the Lushan M_(S)7.0 earthquake sequence in 2013 changed more obviously with time than that of the Lushan M_(S)6.1 earthquake sequence in 2022.In the early period after the two mainshocks,a few aftershocks were detected by the Omi-R-J model,and the completeness magnitude detected in the stable period of the two earthquake sequences was both about 1.8.The difference between the p-values of the two Lushan earthquake sequences was small,showing a relatively normal attenuation process of the two sequences.k-value of the M_(S)7.0 earthquake sequence was significantly larger than that of the M_(S)6.1 sequence;this may be the result of the relatively more aftershocks or the strong aftershocks of the M_(S)7.0 sequence.b-value of the M_(S)7.0 earthquake sequence was smaller than that of the M_(S)6.1 sequence;this indicated that Lushan area was still in a high-stress state after the 2013 M_(S)7.0 earthquake,but after the 2022 M_(S)6.1 earthquake the stress reached a relatively low level.The efficiency evaluation of the N-test method showed that in the initial stage of the two earthquake sequences the aftershock forecasting was efficient.Based on the next day’s data,the forecasting of the aftershocks on the second day after the mainshock only failed once,while the forecasting of the aftershocks of the successive 3 days after the second day of the mainshock did not fail.

关 键 词：芦山地震 Omi-R-J模型 检测率 序列参数 余震预测效能评估 

分 类 号：P315.725[天文地球—地震学]