2011-2014年3次于田MS≥5.0地震序列重定位及其发震构造  

Relocation of three Yutian M_S≥5.0 earthquake sequences during 2011—2014 and their seismogenic structures

作　　者：刘建明[1] 吴传勇[1,2] 王琼[1] 孔祥艳[1,3] 陈向军[1] 

机构地区：[1]新疆维吾尔自治区地震局,中国乌鲁木齐830011 [2]中国地震局地质研究所地震动力学国家重点实验室,中国北京100029 [3]中国地震局地球物理研究所,中国北京100081

出　　处：《地震学报》2016年第5期671-683,813,共13页Acta Seismologica Sinica

基　　金：地震科技星火计划攻关项目(XH16041)资助

摘　　要：基于新疆区域数字地震台网震相观测报告,采用双差定位方法对2011—2014年阿尔金断裂带西南端NE向张性剪切段附近的3次于田MS≥5.0地震序列进行了重定位,并对其余震分布及发震构造等进行了分析.结果表明:2011年于田MS5.5地震的发震构造为阿尔金断裂,该地震同时触发了阿尔金山前普鲁断裂的中小震活动,地震序列呈近NS向长条带状分布;2012年于田MS6.2地震序列沿NNE向分布,发震构造为苦牙克断裂;2014年于田MS7.3地震序列沿NE和NNE方向展布,其中NE走向的余震序列沿阿尔金断裂走向有3处余震丛集分布,由此推测该余震低活动区是由于断层内存在一较大凹凸体,终止了破裂的传播所致,发震构造为阿什库勒断裂和苦牙克断裂.此外,地震序列截面特征显示,2011—2014年3次于田MS≥5.0地震序列基本贯通了阿尔金断裂带西南端的次级断裂和普鲁断裂.Based on the phase observation reports of Xinjiang regional digital seismic network,this paper relocated the three Yutian MS≥5.0earthquake sequences in the southwestern segment of the Altyn Tagh fault during 2011—2014by using the double-difference location algorithm,and then analyzed the distribution of aftershocks and seismogenic structure of the sequences.The results show that the seismogenic structure of the Yutian MS5.5earthquake in2011 is the Altyn Tagh fault,meanwhile small earthquakes were triggered in Pulu fault,and the earthquake sequence is distributed in nearly NS direction.The Yutian MS6.2earthquake sequence in 2012 is distributed mainly along the NNE direction,and its seismogenic structure is the Kuyake fault.The Yutian MS7.3earthquake sequence in 2014 is distributed in NE and NNE direction.Along the Altyn Tagh fault exist three aftershocks clusters,suggesting that the relocated small earthquakes may be a larger asperity to terminate the spread of the rupture,and its seismogenic structure is Ashikule fault and the Kuyake fault.In addition,characteristics of section of the Yutian sequences indicate that the secondary faults at the southwestern segment of the Altyn Tagh fault and the Pulu fault were ruptured by the three Yutian MS ≥5.0earthquake sequences during 2011--2014.

关 键 词：阿尔金断裂带西南端 地震序列 双差定位 震源机制 发震构造 

分 类 号：P315.2[天文地球—地震学]