资源环境科技发展态势分析平台

The 2021 Mw7.3 Maduo (Qinghai, China) earthquake ruptured ∼160 km along a poorly known secondary fault inside the Bayanhar block on the northern Tibetan plateau, which is generally parallel to the Kunlun fault. Here we integrate the interseismic (2015-2020) and coseismic geodetic observations to quantify the interseismic strain rate, fault geometry and coseismic slip distribution. Our results reveal that the seismogenic fault is featured by the low (<20 nanostrain/yr) and nearly undetectable interseismic strain rate. Three-dimensional displacement fields and coseismic strain maps demonstrate the spatial variations of rupture kinematics due to the change of fault geometry. Our study reveals the steeply north-dipping fault geometry of the seismogenic fault. The majority of coseismic slip occurred between 0- and 15-km with slight shallow slip deficit, which not penetrates through the inferred elastic upper crust (∼20-25 km). Our study highlights the tectonic and geometric control on fault kinematics of the Maduo earthquake.