周成^1,,
马张烽¹,
蒋弥^2,,
1. 河海大学地球科学与工程学院, 南京 211100
2. 中山大学测绘科学与技术学院, 广东 珠海 519082

基金项目: 国家自然科学基金（41774003，42074008），中央高校基本科研业务费专项资金（B210203079）资助


详细信息

作者简介: 周成, 男, 1997年生, 硕士生, 主要从事InSAR数据处理与地球物理学研究.E-mail: zhoucheng@hhu.edu.cn

通讯作者: 蒋弥, 男, 1982年生, 博士, 主要从事InSAR数据处理与统计推断方面的研究工作.E-mail: jiangmi@mail.sysu.edu.cn

中图分类号: P223;P315

收稿日期:2020-09-25
修回日期:2021-04-07
上线日期:2021-06-10

Re-exploration of fault dipping direction in Iran Sang sefid 2017 M_W6.1 earthquake using imaging geodesy

ZHOU Cheng^1,,
MA ZhangFeng¹,
JIANG Mi^2,,
1. School of Earth Sciences and Engineering, Hohai University, Nanjing 211100, China
2. School of Geospatial Engineering and Science, Sun Yat-Sen University, Zhuhai Guangdong 519082, China


More Information

Corresponding author: JIANG Mi,E-mail:jiangmi@mail.sysu.edu.cn

MSC: P223;P315

--> Received Date: 25 September 2020
Revised Date: 07 April 2021
Available Online: 10 June 2021


摘要
摘要:在盲断层参数未知的情况下，确定断层模型参数是获取震源机制的基础，也是地震风险性分析的首要任务.2017年伊朗桑塞菲德M_W6.1地震倾角的确定作为盲断层参数确定的一个宝贵实例，在研究观点上仍存在诸多争议.为更好地解释此次地震断层倾角，本文先基于弹性半空间模型构建了东北倾和南倾两种备选的单一平面断层模型.在此基础上，利用哨兵1号和ALOS-2提供的影像大地测量数据联合解算的二维同震形变揭示了两种不同断层模型的逆冲走滑运动特性以及俯冲带逆冲断层破裂模式.为进一步分析更多断层细节并充分解释断层倾向，本文以二维形变数据为约束采用最小二乘动力学反演和贝叶斯反演分别获取了两种潜在断层的最优断层参数和滑动分布并着重分析了两种方法反演结果的各向异性，结果表明东北倾断层具有较小残差且滑动分布更合理.通过分析主震后重定位的59次余震结果发现余震走向分布以及深度延伸方向与东北倾断层模型更吻合，并且东北倾向断层走向与伊朗东北部已知活动断层基本平行，因此可以作为桑塞菲德地震的发震断层为WNW-ESE走向的进一步佐证.本文研究的断层参数为走向314.67°，倾角41.5°，平均滑动角128.8°，断层特征为东北倾逆冲兼具右旋走滑，滑动分布主要集中在沿走向6~22 km处，最大滑动量为7 km深处的1.09 m，断层破裂并未到达地表，反演矩张量为1.427×10¹⁸ N·m，相当于M_W6.07矩震级地震.
关键词: 盲断层/
桑塞菲德/
同震形变/
InSAR/
倾向确定

Abstract:The first step of earthquake risk analysis is to determine the blind fault parameters. There are many disputes about the parameter determination of each blind fault. In this paper,we took 2017 M_W6.1 Sang sefid earthquake as an example. First,we defined two possible fault models based on the elastic half space model. On this basis,the 2D (East-West and Up-Down) co-seismic deformation is inverted by Sentinel-1 and ALOS-2 ascending and descending InSAR data. Results of two fault models reveal the characteristics of the rupture mode as well as the thrust features in the subduction zone. For more details of the fault and fully explaining the dipping angle of the fault,we used constrained least squares and bayesian inversion methods respectively obtained the optimal fault parameters and derived the anisotropy of two fault models. The inverted slip distribution showed that the northeast dipping fault owned smaller residual and its slip distribution was more reasonable. By further analyzing the 59 relocated aftershocks,we found that the slip distribution and depth extension of the aftershocks are more consistent with the northeast dipping model. Besides,the strike of the northeast dip fault is basically parallel to the known active fault in the northeast of Iran. Therefore,it can be regarded as a further evidence of the Sang sefid earthquake's seismological fault as a WNW-ESE fault. The fault parameters we obtained in this paper are strike 314.67 degrees,dip 41.5 degrees,and the average rake 128.8 degrees. The fault features northeast dip thrust with right-lateral strike slip. The inverted slip mainly distributed at 6~22 km along the strike direction. The maximum slip of 1.09 m located at a depth of 7 km. This earthquake did not rupture the surface,and the moment tensor was 1.427×10¹⁸N·m,equivalent to the M_W6.07 earthquake.
Key words:Blind fault/
Sang sefid/
Coseismic deformation/
InSAR/
Dipping determination



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