Abstract:On January 8th, 2022, an MS6.9 earthquake occurred in Menyuan Country, Qinghai Province. To study the co-seismic surface displacement caused by the Menyuan earthquake, we proposed four different dislocation models based on the data of seismogenic fault, and four co-seismic surface displacement fields induced by the Menyuan earthquake were calculated with the analytical solution of surface displacement proposed by Okada. Combined with the field observation data, the sliding form of the seismogenic fault and the associated effect on the surrounding surface were discussed. The results show that the the west side of Lenglongling fault extending to the Tolaishan fault is preliminarily judged as the seismogenic fault of the earthquake. The fault is dominated by left-lateral strike-slip, and the maximum dislocation on the fault reaches about 4 m. Southwest surface of the epicenter moves in the NE direction, and the southeast side moves in the SE direction; the northwest and northeast sides move in the direction of NW and SW, respectively. A small area near the epicenter has a horizontal surface displacement of more than 1.5 m, and there is a vertical surface displacement of more than 0.5 m along the rupture zone. In-situ monitoring results show that the maximum horizontal dislocation is about 2.1~2.3 m, and the maximum vertical dislocation in some areas reaches 0.7 m. Taking the epicenter as the center, the influence range of surface displacement caused by fault is about 30 km × 36 km, and the surface displacement within this range is greater than 0.1 m. The study can provide a reference for the post-earthquake recovery and the subsequent project fortification in this area.