The 1400 km-long left-lateral strike-slip Xianshuihe-Anninghe-Zemuhe-Xiaojiang fault system (XXFS) is one of the largest faults cutting through eastern Tibet and contributing its eastward motion (e.g., Allen et al., 1991;Tapponnier et al., 2001;Tapponnier & Molnar, 1977). East of the Tibetan Plateau, the XXFS extends across the Sichuan and Yunnan provinces and merges with the Red River fault (Figure 1). The XXFS has been one of the most seismically active faults in mainland China, as attested by a detailed history of past earthquakes for the last three centuries (e.g., Allen et al., 1991;Wen, Ma, et al., 2008). Indeed, during that period, historical records indicate more than 35 earthquakes with magnitude estimated to be larger than 6. Additional historical records dating back to the XIV th century indicate that each of the four faults has hosted at least one large M > 7.5 earthquake and the largest event with an estimated magnitude reaching eight occurred in 1833 along the Xiaojiang fault in Yunnan. According to the earthquake history

Integrating newly‐processed Interferometric Synthetic Aperture Radar (InSAR) and available Global Positioning System (GPS) data, we obtained a dense interseismic velocity field across the Tuosuo Lake segment of the Kunlun fault. Using a Bayesian approach, we obtained the spatial distribution of fault slip and coupling. The slip rate below the locking depth, which represents contemporary steady‐state faulting, demonstrates an overall decrease, and decreases non‐monotonically toward the eastern fault tip in the range of ∼5–11 mm/a. Two strongly locked zones are identified, extending 100–120 km along‐strike and being separated by narrow sections of moderate coupling. These locked zones were likely ruptured during the 1937 M 7.5 Huashixia earthquake. The estimated moment accumulation rate provides a recurrence time of 428 ± 57 years for an earthquake similar to the 1937 event. The Maduo Mw 7.3 earthquake on 21 May 2021 imposed stress loading on the locked zones, equivalent to tectonic loading of ∼10 years, implying increased seismic hazard along the Kunlun fault.

On 17 November 2017, a Mw 6.5 earthquake occurred in Mainling County, Nyingchi City, China. The epicenter was located in the Namche Barwa region of the eastern Himalayan syntaxis. Here, we have derived coseismic deformation from Global Positioning System (GPS) data and ascending Sentinel-1A Synthetic Aperture Radar (SAR) data. Based on a joint inversion of the two datasets, we obtained the coseismic slip distribution along a curved, northeast trending, and high-angle (dip angle of 75°) thrust fault. Our results show that the seismic moment release was 7.49 × 1018 N∙m, corresponding to a moment magnitude of Mw 6.55. The maximum slip was 1.03 m and the main rupture zone extended to a 12 km depth. The earthquake may have been related to the release of strain accumulated during the subduction of the Indian plate beneath the Eurasian continent. We identified a high strain rate and low b-values around the epicentral area before the earthquake, indicating that the earthquake was nucleated under a high strain/stress state. The data indicate two regions, southwest and southeast to the epicenter (the eastern Main Himalaya Thrust and northern end of the Sagaing fault), which remain under high stress/strain conditions and pose a significant seismic hazard.

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