Coseismic Slip Model of the 2021 Maduo Earthquake, China from Sentinel-1 InSAR Observation

Abstract

The 2021 Maduo earthquake occurred in the interior of the Bayan Har block of the Tibetan Plateau. We used space-born radar interferometry to study the coseismic deformation of this earthquake. Sentinel-1 InSAR observations along ascending and descending orbits provide the coseismic deformation. Pixel offset tracking method is used to complement InSAR observations near the rupture zone. The surface trace of the ruptured fault can be clearly mapped by InSAR observations. We constructed a three-dimensional coseismic slip model constrained by interferograms and pixel offset tracking in the form of a geodetic inverse problem. The coseismic slip model demonstrates that: (1) the Maduo earthquake was a left-lateral strike-slip event with moment magnitude of 7.4; (2) the peak slip is approximately 8 m and is located at a depth of 4 km; (3) a ‘shallow slip deficit’ of the Maduo earthquake is observed; (4) the ruptured faults are found to be dipping northward with a high dipping angle (80 degrees). This study has important implications on earthquake hazard evaluation of the Bayan Har block.