Seismic landslide hazards assessment along the Xianshuihe fault zone, Tibetan Plateau, China

The Xianshuihe fault zone is a large active left-lateral strike-slip fault zone in the southeast margin of Qinghai-Tibet Plateau, Southwest China, the geomorphology and geological structure along the fault zone is complex, and historical earthquakes occur frequently, which induce a large number of seismic landslide disasters, causing a huge impact on major construction projects and people's lives and properties.For the long-term prevention of seismic landslides in the Xianshuihe fault zone, an area of about 20 km on both sides of the Xianshuihe fault zone was selected for remote sensing interpretation and field geological survey, a total of 399 historical seismic landslides were found in the region, with overall characteristics of high remote, one slide to the bottom and cracked but not slipped.On the basis of studying and analyzing the disaster background and development and distribution characteristics of regional geological disasters, the Newmark model was used to complete the seismic landslide hazards assessment with exceeding probability 10% of 50 years in Xianshuihe fault zone.The results showed that the extremely high-risk area, high-risk area, medium-risk area, and low-risk area of seismic landslides account for 6.28%, 11.77%, 33.33%, and 48.62% of the total area of the study area, respectively.The Kangding-Moxi section and the vicinity of Dadu River are areas with high seismic landslide hazards.63.66% of seismic landslides are distributed in extremely high and high seismic landslide hazards areas, the test results of the success rate (ROC) curve show that the accuracy of the landslide risk assessment is 74.3%, and the accuracy of the evaluation results is high.The Sichuan-Tibet Railway under planning and construction extends from Luding County and Kangding City, where there is a high risk of seismic landslide.Therefore, it is necessary to strengthen the evaluation and prevention of potential seismic landslide hazards near the railway tunnel entrance in the project planning and construction.The seismic landslide hazards zoning results of the Xianshuihe fault zone will provide reference materials and scientific guidance for the prevention and control of seismic and geological disasters in this region and the construction of the Sichuan-Tibet railway.