XU Chong;XU Xiwei;YU Guihua;WU Xiyan
2036 landslides were triggered by the 2010 Yushu earthquake, in a total area of 1.194km2. The Landslide Area Percent (LAP) and the Landslide Number Density (LND) are selected as two indices for the susceptibility analysis of landslide impact factors. The impact factors of landslides include the earthquake impact factors such as the epicenter, the macro-epicenter, the main co-seismic surface fault-rupture, the Peak Ground Acceleration (PGA), and the co-seismic displacement; the topography impact factors such as the elevation, the slope angle, the slope aspect, the slope curvature, the slope position, and the drainages; the geology impact factors such as the lithology and the faults; and other impact factors such as the roads and the Normalized Difference Vegetation Index(NDVI). The results show that: (1) Both LAP and LND have strong positive correlations with the distance from the main co-seismic surface fault-rupture, and also have positive correlations with the macro-epicenter and co-seismic displacement except for individual classifications, but the correlations between the landslide occurrences and the epicenter, and PGA are not clear-cut. (2) The greater the slope angle, the higher the probability of landslide occurrence; the elevation less than 4000m sees a high susceptibility to landslide occurrences; it can be found that the slopes facing NE, E, and SE see relatively higher LAP and LND values than other directions; the higher the slope position, the higher the landslide susceptibility except for flat slope; landslides have positive correlations with the distance from drainages; rough slopes are more prone to landslide occurrence than smooth slopes. (3) The stratums of Q4al-pl (Alluvium, fluvial deposits, gravel), N (Quartz sandstone, breccia), and T3kn1 (Feldspathic sandstone, siltstone, slate, limestone, phyllite) see concentrated landslide activities, the correlation between the landslide occurrences and the faults is not clear-cut. (4) The closer to roads and the more sparse of the vegetation, the more susceptibility to landslide occurrences.
