GPS determined coseismic slip of the 2021 Mw7.4 Maduo, China, earthquake and its tectonic implication

The 2021 M(w)7.4 Maduo earthquake occurred on the Jiangcuo fault within the Bayan Har block in eastern Tibet. It is a rather unique event and attests that large earthquakes can occur in the interior of major tectonic blocks within the Tibetan plateau. By processing GPS data observed in the eastern Tibet region, we produce a data set documenting 3-D coseismic displacements of the Maduo earthquake. Using the data set to constrain a coseismic slip model, we find that the earthquake ruptured a nearly vertical fault about 170 km in length, with similar to 90% of the moment released in the shallow layer above 20 km depth. The maximum slip of similar to 3.6 m occurred near the surface around a bend in the east segment of the fault. The overall seismic moment release is 1.82 x 10(20) N m and is equivalent to M(w)7.4. Driven by the eastward extrusion of the Tibetan plateau, the deformation field in eastern Tibet is dominated by left-lateral shear, with the strikes of the tectonic faults rotating clockwise from west to east along with the shear stress orientation. This deformation pattern explains the mechanisms of earthquakes along block boundary faults, as well as the ones on faults within the blocks. The Jiangcuo fault is located similar to 70 km south of the East Kunlun fault and could be connected to the Kunlun Mountain Pass fault to its WNW that ruptured during the 2001 Kokoxili earthquake, and a seismic gap of similar to 240 km long between the two faults is worth special attention for its increased earthquake potential.

Automated summary

This study discusses the characteristics and potential earthquake risks associated with the M(w)7.4 Maduo earthquake that occurred in the eastern Tibetan region in 2021.