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.