Coseismic and Pre-seismic Deformation Characteristics of the 2022 MS 6.9 Menyuan Earthquake, China
Coseismic and Pre-seismic Deformation Characteristics of the 2022 MS 6.9 Menyuan Earthquake, China
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DOI：
10.1007/s00024-022-03128-3
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发表时间：
2022-08
影响因子：
2
通讯作者：
Nannan Guo;Yanqiang Wu;Qin Zhang
中科院分区：
文献类型：
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作者：
Nannan Guo;Yanqiang Wu;Qin Zhang
2022年1月8日，青海门源发生6.9级地震，震中位于冷龙岭断裂和托来山断裂的断阶上，震中为中国。利用干涉合成孔径雷达(InSAR)和全球导航卫星系统(GNSS)资料建立了物理模型，对断层滑动分布、断层耦合系数、断层滑动赤字和应变率进行了反演，研究了与地震相关的同震形变和震前形变。初步反演结果如下：(1)干涉合成孔径雷达同震形变图样表明，左旋走滑形变发生在NW-SE方向，视线方向最大相对位移为1.3M。(2)同震滑动主要发生在30 × 25M范围内，深度为0~8M。最大断层滑动为3.81米，力矩震级为6.6级。(3)在断层耦合反演的基础上，门源地震前发震断层被强烈闭锁(>； 0.96)，最深可达 ~ 10 km。断层走向方向的同震破裂带明显小于震前闭锁区。(4)震前应变速率表现为NE-SW向挤压变形和NW-SE向拉伸变形，反映了孕震区较大的左旋应变积累，最大剪切应变率为2.6 × 10-8/年。因此，必须重视与孕震区相邻的托莱山断裂和冷龙岭断裂所造成的地震危险性。
On January 8, 2022, theMS6.9 Menyuan earthquake occurred in Menyuan, Qinghai province, China; the epicenter was on the fault terrace of the Lenglongling and Tuolaishan faults. To investigate the coseismic and pre-seismic deformation associated with the event, we constructed physical models using interferometric synthetic aperture radar (InSAR) and global navigation satellite system (GNSS) data and inverted the fault slip distribution, fault coupling fraction, fault slip deficit and strain rate. The primary inversion results were as follows: (1) The InSAR coseismic deformation pattern indicates that the left-lateral strike-slip deformation occurred in the NW–SE direction, with the maximum relative displacement in the line-of-sight direction being 1.3 m. (2) The coseismic slip mainly occurred in a 30 × 25 km region at a depth of 0–8 km. The maximum fault slip was 3.81 m with a moment magnitude (MW) of 6.6. (3) Based on the fault coupling inversion, the seismogenic fault was strongly locked (> 0.96) up to a depth of ~ 10 km before the Menyuan earthquake. The coseismic rupture zone in the fault strike direction was significantly smaller than the pre-seismic locked region. (4) The pre-seismic strain rates revealed NE–SW compressive and NW–SE tensile deformations, reflecting a considerable left-lateral strain accumulation in the seismogenic region, with a maximum shear strain rate of 2.6 × 10–8/year. Therefore, attention must be paid to the seismic hazards posed by the Tuolaishan and Lenglongling faults adjacent to the seismogenic region.