Interseismic slip rate and locking along the Maqin–Maqu Segment of the East Kunlun Fault, Northern Tibetan Plateau, based on Sentinel-1 images

Abstract

Abstract The East Kunlun Fault (EKF) is one of the most active left-lateral strike-slip faults of the Tibetan Plateau and defines the northern boundary of the Bayan Har Block. Many strong earthquakes have occurred over the past century in the western segment of the EKF, whereas few historical earthquakes have occurred in the eastern segment, that is, the Maqin–Maqu segment (MMS). Therefore, the MMS is widely recognized as a seismic gap with high risk. For this purpose, the Interferometric Synthetic Aperture Radar (InSAR) technique was used to process Sentinel-1 images of the MMS in the EKF to determine the interseismic deformation velocity field during 2014–2019. Then, the slip rate and locking of the MMS were obtained. The results are as follows. (1) The slip rate gradually decreased from west to east along the Maqin–Maqu Segment, i.e., from ~8 mm/year to ~2 mm/year, and a significantly low slip-rate zone exists near the Maqin Segment. (2) Four asperities having a high seismic risk were identified in the Maqin–Maqu Segment. (3) Based on the determined slip rate and previous studies, we propose that the deformation of the Bayan Har Block can be explained with a nonrigid passive bookshelf model.