Spatial Distribution Patterns of Earthquake-Induced Landslides in the Loess Region of Tongwei County, Gansu Province

This paper takes Tongwei, Gangu, Wushan and Qin'an counties involved in the 1718 Tongwei earthquake as the study area, combines with the case investigation of earthquake damage and historical landslide data, and uses the statistical analysis model to select 10 impact factors related to topography, geology, earthquakes and human activities in the study area.Finally, the relative contribution and coupling effect of different influencing factors to the spatial distribution of earthquake-induced loess landslides are discussed by principal component analysis. The results show that: (1) The loess seismic landslides in the study area are concentrated in the south-facing slope areas with elevation of 1000-1300 m, slope of 10-20°, topographic relief of 0-30 m, 1200-1600 m away from rivers, 2-8 km away from active faults, intensity of X, land use types of grass and farmland, and relatively weak lithology. (2)Further verified that the prone areas of loess landslides in the study area are the areas near rivers with an elevation of 1600-1900m and a slope of 10-20 degrees, and the areas covered by thick loess layers with a distance of 4-12 km from active faults.