基于GNSS的青海玛多M7.4级地震的地表形变分析

2021年5月22日，青海省玛多县发生M7.4级地震，地震对区域基准站造成了影响. 本文收集了距震中400 km以内的青海省全球卫星导航系统(GNSS)连续运行参考站(CORS)的高频观测数据，以国际GNSS服务 (IGS)站和陆态网为参考基准，分别采用静态模式和动态模式分析了震后地表三维形变. 结果表明:站点位移量级随震中距的加大而呈现衰减趋势，其中距震中约35 km的江多站(JDUO)产生东偏南28.0 cm的永久性位移. 整体来讲，地震对100 km内的震源区的影响表现为走滑型运动，与震源机制相吻合，区域运动特征整体表现为拉张运动，北西-南东(NW-SE)向拉张和北东-南西(NE-SW)向挤压. 

The analysis of ground deformation about Qinghai Maduo M7.4 earthquake based on GNSS

On May 22, 2021, Beijing time, an M7.4 earthquake occurred in Maduo, Qinghai province, which affected the regional stations. In this paper, we collected high-frequency observation data of Global Navigation Satellite System (GNSS) continuously operating reference stations (CORS) in Qinghai Province , which is less than 400 km from the epicenter. Using International GNSS Service (IGS) stations and China continental tectonic environment monitoring network as reference stations, static and dynamic models were used to analyze the three-dimensional surface deformation after the earthquake. The results show that, the displacement magnitude of the site shows a trend of attenuation as the epicenter distance increases. Among them, the Jiangduo station, which is about 35 km away from the epicenter, produces a permanent displacement of 28.0 cm to the south east. On the whole, the impact of the earthquake on the focal area within 100 km is shown as a strike-slip motion, which is consistent with the focal mechanism. The regional motion characteristics are generally shown as extensional-compression motion, NW-SE extension and NE-SW compression.