A hybrid source mechanism of the 2017 Mw 6.5 Jiuzhaigou earthquake revealed by the joint inversion of strong-motion, teleseismic and InSAR data
A hybrid source mechanism of the 2017 Mw 6.5 Jiuzhaigou earthquake revealed by the joint inversion of strong-motion, teleseismic and InSAR data
复制标题
强震、远震和InSAR数据联合反演揭示2017年九寨沟6.5级地震混合震源机制
DOI：
10.1016/j.tecto.2020.228538
复制
发表时间：
2020-08
期刊：
影响因子：
2.9
通讯作者：
Zhang Wenbo
中科院分区：
文献类型：
--
作者：
Zheng Ao;Yu Xiangwei;Xu Wenbin;Chen Xiaofei;Zhang Wenbo
由于发生在旅游旺季，2017年九寨沟（中国）Mw6.5地震造成了破坏性破坏。此次事件的发震断层仅被推测为虎牙断层的北延，而现场勘察并未发现明显的地表破裂现象。以往的研究和已发布的矩张量解表明，九寨沟地震以左旋走滑为主，带有部分正滑分量。似乎难以理解的是，这次事件中发生了正常滑移，因为震中位于汇聚块体的边界附近。因此，有必要建立一个合理、精细的震源破裂模型来研究这种盲断层及其在该地区复杂断层系统中的作用。结合天基大地测量、远震或区域地震观测可以提供有关地震破裂的详细信息。我们首先尝试使用贝叶斯方法和合成孔径雷达干涉图 (InSAR) 来确定断层几何形状。然后根据重新定位的余震分布细化断层几何形状，构建两段断层模型。基于两段模型，通过强震、远震体波和InSAR数据联合反演，解析了2017年九寨沟地震的震源破裂过程。反演结果揭示了除走滑分量外正滑和逆冲滑共存的混合源机制。我们认为，巴颜喀拉地块东北缘的下地壳流挤压造成的向东运动是造成这种断层行为的原因。同震库仑应力变化显示塔藏断裂西段存在显着的应力载荷，增加了其地震危险性。由于发震断裂东南部余震较少，虎牙断裂北段地震活动可能增强也值得进一步关注。
As occurred during the tourist season, the 2017Mw6.5 Jiuzhaigou (China) earthquake led to destructive damages. The seismogenic fault of this event was merely speculated to be the northern extension of the Huya fault, while no apparent surface ruptures were discovered in the field investigation. Previous studies and released moment tensor solutions indicated the Jiuzhaigou earthquake was dominated by left-lateral strike slip with partial normal-slip component. It seems unintelligible that the normal slip occurred in this event as the epicenter was located near the boundary of convergent blocks. Hence, a reasonable and elaborate source rupture model is necessary to investigate such a blind fault and the role it plays in the complex fault system of this region. Combining space-based geodetic, teleseismic or regional seismic observations can provide detailed information about earthquake ruptures. We first attempted to determine the fault geometry using the Bayesian approach with synthetic aperture radar interferograms (InSAR). And then the fault geometry was refined based on the relocated aftershock distribution, and a two-segment fault model was constructed. Based on the two-segment model, we resolved the source rupture process of the 2017 Jiuzhaigou earthquake through the joint inversion of strong-motion, teleseismic body-wave and InSAR data. The inversion results reveal a hybrid source mechanism, in which normal and thrust slips coexist besides the strike-slip component. We suggest that the eastward motion with the extrusion of the lower crustal flow in the northeastern margin of the Bayan Har block is responsible for such a faulting behavior. The co-seismic Coulomb stress changes show a significant stress loading in the western segment of the Tazang fault, increasing its seismic hazard. Due to the lack of aftershocks to the southeast of the seismogenic fault, the probably enhanced seismicity in the northern segment of the Huya fault is also worth further attention.
登录
查看更多内容
DOI：
10.6038/cjg20171029
发表时间：
2017
期刊：
地球物理学报
影响因子：
--
作者：
任俊杰;徐锡伟;张世民;罗毅;梁欧博;赵俊香
通讯作者：
赵俊香
影响因子：
3.3
作者：
Jia Cheng;Y. Rong;H. Magistrale;Guihua Chen;Xi-wei Xu
通讯作者：
Jia Cheng;Y. Rong;H. Magistrale;Guihua Chen;Xi-wei Xu
影响因子：
5.2
作者：
Wenbin Xu
通讯作者：
Wenbin Xu
根据强震数据运动波形反演估算2016年新西兰凯库拉地震震源破裂过程
影响因子：
2.8
作者：
Ao Zheng;Mingfeng Wang;Xiangwei Yu
通讯作者：
Xiangwei Yu
DOI：
10.6038/cjg20171032
发表时间：
2017
期刊：
地球物理学报
影响因子：
--
作者：
季灵运;刘传金;徐晶;刘雷;龙锋;张致伟
通讯作者：
张致伟