Spatial slip rate partitioning along the Xianshuihe Fault Zone, eastern Tibetan Plateau

This is the authors' abstract. We don't add key points for this paper.

The Xianshuihe Fault Zone (XSHF) frequently experiences strong earthquakes owing to its high slip rate; particularly, the Kangding segment within the XSHF is structurally complex. To conduct an accurate regional seismic hazard analysis of XSHF, it is necessary to understand the slip rates of the branch faults of the Kangding segment. In this study, we aimed to determine the slip rates of the Yalahe Fault (YLHF) and the northwestern segment of the Zheduotang Fault (ZDTF), which are both parts of the Kangding segment. We employed tectonic geomorphology, topographic data, terrestrial laser scanning, precise offset measurements using LaDiCaoz_v2 software, and 10 Be cosmogenic nuclide dating techniques. Our analysis showed slip rates of 3.5 ± 0.3 mm·yr −1 and 2.3 ± 0.2 mm·yr −1 since 12.7 ka and 7.8 ka for the YLHF, implying a decreasing slip rate trend post the Holocene period. Furthermore, we obtained slip rates of 1.9 ± 0.3 mm·yr −1 since 42.7 ka and 1.8 ± 0.2 mm·yr −1 since 15.7 ka for the northwest segment of the ZDTF. Notably, these slip rates are significantly lower than those observed for the southeastern ZDTF. Furthermore, in the late Quaternary, the combined slip rate for the XSHF reached a maximum of 9.9–15.5 mm·yr −1 . We also observed that the Anninghe Fault inherited 48.2 % of slip rate from XSHF. These findings provide a comprehensive overview of slip rate partitioning among branch faults in the Kangding segment, offering novel insights into the seismic behavior of the XSHF and improving regional seismic hazard assessment. • Slip rate of the YLHF revealed a decreasing tendency during post-Holocene. • Kangding segment is representative of the region and has the highest slip rate. • Faults partition the horizontal slip rate of the XSHF towards the southwest.