罗钧^1,,
左可桢^1,2,
赵翠萍^1,,
1. 中国地震局地震预测研究所, 北京 100036
2. 中国地震局地球物理研究所, 北京 100081

基金项目: 中国地震局地震预测研究所基本科研业务费专项（2018年度）所重点项目课题（2018IEF010202）辽南地区地震震源及应力场特征研究，中国地震局地震预测研究所基本科研业务费专项（2021年度抓大震科技支撑项目）金沙江下游水库区地震加密监测和震情跟踪（2021IEF0710）共同资助


详细信息

作者简介: 罗钧, 女, 1988年生, 助理研究员.主要从事地震震源机制、区域应力场、水库应力触发模拟方面的研究.E-mail: luojun@ief.ac.cn

通讯作者: 赵翠萍, 女, 1967年生, 研究员.主要从事地震学和水库地震等方面的研究.E-mail: zhaocp@ief.ac.cn

中图分类号: P315

收稿日期:2020-09-11
修回日期:2021-04-13
上线日期:2021-07-10

Focal mechanism solutions and seismogenic faults of the Yutian M_S6.4 focal area on June 26^th, 2020

LUO Jun^1,,
ZUO KeZhen^1,2,
ZHAO CuiPing^1,,
1. Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China
2. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China


More Information

Corresponding author: ZHAO CuiPing,E-mail:zhaocp@ief.ac.cn

MSC: P315

--> Received Date: 11 September 2020
Revised Date: 13 April 2021
Available Online: 10 July 2021


摘要
摘要:利用国家区域台网23个台P、S波到时资料及区域台网12个宽频带波形数据，对新疆于田地区2008年10月1日至2020年12月8日期间的地震展开重定位.对2020年6月26日于田M_S6.4主震、M_S4.6前震和M_S4.5余震展开震源机制解求解.综合震源区历史震源机制解对于田地区地震活动展开系统分析.结果表明：（1）2020年6.26于田地震的发震断裂是阿尔金断裂带西段SN向正断层活动系统中一条位于琼木孜塔格峰以东山麓地带的NNE走向的拉张型断裂，质心深度6 km，矩震级M_W6.1，余震活动尺度小于20 km.M_S4.6前震和M_S4.5余震的机制解与主震一致，均为正断层性质；（2）除2014年M_S7.3地震及其余震表现为左旋走滑活动外，2008年M_S7.3、2012年M_S6.2以及2020年M_S6.4都是位于康西瓦断裂和郭扎措断裂之间正断层地震.这种正断层的存在与地质研究给出的阿尔金断裂西段的康西瓦断裂和郭扎措断裂之间存在一组SN向活动的次级正断层相吻合.阿尔金断裂带以西的地震活动表现出多条近NS向集中展布的地震条带，NS向次级断层活动明显.2008年以来阿尔金断裂带西段的构造活动以这些次级断层的活动为主.
关键词: 阿尔金断裂带西段/
2020年6月26日于田M_S6.4地震/
重定位/
震源机制解/
发震构造

Abstract:In this study, we firstly relocate events recorded from Octorber 1^st, 2008 to December 8^th, 2020 in Yutian area, Xinjiang province, using P and S phases of 25 National Regional Seismic Network and 12 broadband waveform data. Besides, we calculate focal mechanisms of the M_S6.4 June 26^th 2020 and its M_S4.6 foreshock, M_S4.5 aftershock. Systematical analyses of seismicity features are conducted by mixing these two kinds of results together. Results show conclusions as following. (1) The seism genic fault of the M_S6.4 June 26th, 2020 Yutian earthquake is a NNE trending tensile fault. This fault belongs to the eastern foothill of the Qiongmuztag peak in the SN trending normal fault active system of the Altun fault zones western segments. Its centroid depth is 6km, and its moment magnitude is M_W6.1, and aftershock activity scale is less than 20km. Mechanism solutions of M_S4.6 foreshock and M_S4.5 aftershock are consistent with that of the main shock. All belong to normal faults solutions. (2) Except the M_S7.3 2014 earthquake, the 2008 M_S7.3、2012 M_S6.2 and 2020 M_S6.4 are belong to normal faults lying between the Kangxiwa fault and the Guozhacuo fault. It is consistent with the geological conclusion that both the Kangxiwa fault and Guozhacuo fault are connected by a group of SN trending normal faults in the western segment of the Altun fault. There are a series of events in the western Altun fault zones being characterized by series of NS trending seismic belts nearby. Since 2008, the seismicity of the western segment of the Altun fault zone has been dominated by these secondary faults.
Key words:West segment of the Altun fault zone/
The Yutian M_S6.4 earthquake on June 26, 2020/
Seismicity relocation/
Focal mechanism solutions/
Seism genic structure



PDF全文下载地址:

http://www.geophy.cn/data/article/export-pdf?id=ec588325-fa4c-4d7c-a51f-9e718ead122e