| 2017年九寨沟7.0级地震序列震源机制解和构造应力场特征 |
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| 关键词:Jiuzhaigou earthquake sequence focal mechanism tectonic stress field seismogenic structure |
| 基金项目:中国地震局监测预报司震情跟踪青年课题(编号: 2018010122);四川省地震局地震科技专项(编号: LY1802; LY1817);2018年地震大形势跟踪任务 |
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| 摘要: |
| Focal Mechanism Solutions and Tectonic Stress Field Characteristics of the 2017 Ms7.0 Jiuzhaigou Earthquake Sequence |
| Focal mechanism solutions and stress field for the 2017 Ms7.0 Jiuzhaigou earthquake sequence can help to understand the seismogenic structure and mechanism. Based on the digital waveforms of Sichuan seismic network, the authors calculated focal mechanisms of the Jiuzhaigou earthquake sequence of 59 ML≥3.0 by employing the CAP method and HASH method, and then used the focal mechanism solutions to calculate the stress field through the DRSSI. The nodal plane parameters of the main event are as follows: strike=248°, dip=86°, rake = –169°, and strike =157°, dip=79°, rake = –4°, the moment magnitude of the main shock is 6.31 and the depth is about 5 kilometers, suggesting a strike-slip seismic event. The type of focal mechanisms of ML≥3.0 aftershocks is consistent with the main shock, the depths of the Jiuzhaigou earthquake sequence are between 3 and 10 kilometers. The stress regime around the epicenter area is of the strike-slip type, and the maximum dominant direction is near NWW–SEE, almost consistent with that of the type of focal mechanisms, which shows that the occurrence of the earthquake was mainly controlled by regional stress. In combination with the seismic geological structure, the authors hold that the MS7.0 Jiuzhaigou earthquake was formed by the NW–SE trending SW dipping Shuzheng fault. The E–SE trending horizontal movement of the block of the Bayan Har was strongly blocked by the South China Block, which probably led to the occurrence of this earthquake. |
| QI Yu-ping,LONG Feng,XIAO Ben-fu,LU Qian,JIANG Peng.2018.Focal Mechanism Solutions and Tectonic Stress Field Characteristics of the 2017 Ms7.0 Jiuzhaigou Earthquake Sequence[J].Acta Geoscientica Sinica,39(5):622-634. |
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