【摘要】 2017年8月8日四川省九寨沟县发生M_S 7.0级强烈地震.此次地震震感强烈,影响范围甚广.为了深入研究九寨沟7.0地震序列的时空分布、震源特性以及发震构造等,本文基于区域数字地震台网记录,采用近震全波形矩张量反演方法反演了四川九寨沟M_S 7.0级主震和M_L≥3.5级余震的震源机制解;并使用四川测震台网提供的观测报告,采用双差定位法对九寨沟地震序列进行了重新定位.结果显示:九寨沟7.0级地震是一次以走滑为主的地震事件,地震序列整体呈北西向线性分布,并以主震为中心,向两侧扩展;序列震源机制、重新定位和深度分布结果均显示,以主震为中点分成的两段具有显著的分段差异.综合精定位和矩张量反演结果,推测九寨沟地震的发震断层是一个整体呈北西走向,倾向南西,但又具有显著分段特性的断层,北段呈北北西向,走滑兼逆冲性质,南段北西向,以走滑性质为主.更多还原

【Abstract】 On August 8, 2017, a magnitude 7.0 earthquake struck in Jiuzhaigou County, Sichuan Province. This earthquake was felt strong and affected a wide range. In order to further study the Jiuzhaigou 7.0 earthquake sequence’s spatial and temporal distribution, seismic source characteristic and earthquake structure and so on, this article was based on the digital seismic data recorded by regional network, using the moment tensor inversion method of near-field full waveform to obtain the focal mechanisms of the Jiuzhaigou M_S 7.0 earthquake and M_L≥3.5 aftershock sequence. As well, the Jiuzhaigou earthquake sequence was relocated by the double-difference algorithm using the observation report of Sichuan seismic network.The results showed that the Jiuzhaigou M_S 7.0 earthquake appeared to be strike-slip type mostly, and the sequence was a linear distribution along the north-west, extending to both sides with the main shock as the center. The focal mechanism, relocation and depth distribution results all showed that the two segments with the main earthquake are divided into had significant segmented differences. Integrated relocation and depth distribution results displayed, the seismic fault of the Jiuzhaigou earthquake was a fault which was whole in the north-west, tended to the south-west, but also had significant section features. The north part was a strike-slip and thrust property, north-north-west striking, and the south part was mostly strike-slip property, north-west striking.更多还原