Exploring the Seismogenic Zone on Southeastern Xianshuihe Fault in Eastern Tibetan Plateau by Inverted Interseismic Stress Changes

The Xianshuihe Fault (XSHF) is one of the most active faults in eastern Tibetan Plateau. Seismic risk on southeastern XSHF is a major concern， as most of southeastern XSHF has experienced a lack of large earthquakes for over two hundred years， but has shown higher seismic activity than other segments of the XSHF over the past decade. To explore seismogenic mechanism of southeastern XSHF， an earthquake stress model and the Interferometry Synthetic Aperture Radar (InSAR) data between 2016 and 2020 are used to invert for interseismic stress changes on southeastern XSHF. The results show two seismogenic zones on southeastern XSHF， with high stress accumulations and future seismic risk. One of these zones is the Qianning-Selaha segment， where shear stress continued accumulating after more than one year following the 2014 Kangding earthquake. The other one is the Moxi-Shimian segment， where the following 2022 Luding earthquake occurred two years after the period covered in this study. Compressional normal stress increased near the hypocenter of the Luding earthquake， and frictional strength of this area may rise before the earthquake due to the increment in normal stress. Additionally， a shear stress release area was identified between the Qianning-Selaha and Moxi-Shimian segments during 2016-2020.