2022年1月8日青海门源MS6.9地震GNSS同震形变场及其断层滑动分布

2022年1月8日在青海省海北州门源县发生M_S6.9地震，本次地震是继2016年门源M_S6.4地震后冷龙岭断裂周边发生的又一次强震。确定本次地震的破裂分布对分析该地区震害风险具有重要意义。通过收集震中及周边12个GNSS连续站点和震后加密观测的17个流动站点观测资料，获取了震中100 km范围内29个测站的GNSS静态同震形变场，并以此为约束反演了本次地震同震滑动分布。结果显示，近场GNSS观测到的最大形变量可达1.3 m。反演的最优破裂模型显示该地震主破裂区深度位于0～10 km,滑动破裂出露地表，最大滑动量为4.07 m,地震矩释放能量约1.1×10¹⁹ N·m,对应矩震级M_W6.7。门源地震破裂至地表是造成该地区基础设施破坏的直接原因。

Co- seismic deformation filed and fault- slip distribution of the Menyuan MS6.9earthquake on January 8, 2022, constrained by GNSS observations

On January 8, 2022, an MS6.9 earthquake occurred in Menyuan County, Qinghai Province. It is another strong earthquake occurred in this region after the 2016 Menyuan MS6.4 earthquake, and determining the rupture distribution of this earthquake has great significance for analyzing the seismic damage risk in this area. Based on the observation data from 12 continuous global navigation satellite system (GNSS) stations and 17 mobile stations in the epicenter and its surrounding areas, the GNSS static co- seismic deformation field of 29 stations within 100 km of the epicenter was obtained and the co- seismic slip distribution of the MS6.9 earthquake was inverted. Results show that the maximum deformation observed by near- field GNSS reaches 1.3 m. The optimal rupture model shows that the main rupture zone of the earthquake is concentrated at the depth of 0-10 km; the sliding rupture is exposed to the surface, and the maximum slip is up to 4.07 m; the inverted seismic moment is about 1.1×10¹⁹ N·m, corresponding to MW6.7. The earthquake rupture to the surface is the direct cause of the destruction of infrastructure in this region.