Crustal material eastward extrusion from the Tibetan Plateau is closely related to the strike-slip faults in the SE margin of the Tibetan Plateau. The left-lateral strike-slip Xianshuihe–Xiaojiang fault system (XXFS) is the most active and the largest-scale one. The slip rates along the XXFS is crucial for unraveling the kinematics of the SE margin of the Tibetan Plateau. The central section of the XXFS, also known as the Anninghe–Zemuhe section, was poorly researched owing to its inaccessibility, a lack of high-quality quantitative age data, as well as questionable displacement determination and methodology. In this study, we adopted high-resolution topographic data (terrestrial laser scanning) and high-accuracy dating methods (OSL and 14C) to obtain more reliable slip rates of Anninghe Fault and Zemuhe Fault. The late Quaternary slip rates of Anninghe Fault and Zemuhe Fault were constrained to be 6.9±0.6 mm/a and 11.2±0.4 mm/a, respectively. A large of rate statistics was also conducted along the XXFS. We found that the slip rate of the XXFS is in a narrow range of 12–15 mm/a (slightly increasing from north to south) after taking the Daliangshan Fault into account. Combined with the analysis of the relationship between the active faults and block rotation, we proposed that the uniform high-speed strike-slip along the XXFS largely constrains the clockwise rotation of the SE margin of the Tibetan Plateau.

The Chenghai fault zone, an important part of the Dali fault system, is instrumental in comprehending the crustal deformation of the southeastern margin of the Tibetan Plateau. Detailed remote sensing interpretation and field mapping are used to study the geometry and kinematic characteristics of this fault. The results show that the Chenghai fault zone extends up to 200 km from Jinguan to the south end of the Midu basin, and it truncated and inherited the trace of the Red River fault on the east side of the Midu basin. Furthermore, it is an oblique-slip fault with both normal and sinistral strike-slip component, and the normal component is more significant. The transtensional activity of this fault may have started in the Early Pliocene (5–6 Ma). The average maximum dip-slip rate can be 0.37–0.57 mm/yr, and the maximum left-slip rate is 0.83–1.20 mm/yr. The clockwise rotation of the Dali block resulted in the Z-shaped Dali fault system and the Chenghai fault zone. Moreover, the difference of angular velocity between the inner and the outer arcuate belts divided by the Litang–Dali–Ruili fault system leads to the clockwise rotation of the Dali block.