SENSITIVITY ANALYSIS ON CAUSATIVE FACTORS OF GEOHAZARDS IN EASTERN MARGIN OF TIBETAN PLATEAU

In the eastern margin of Tibetan Plateau, the complicated geomorphology and strong tectonic activities bring frequent and destructive geohazards.Especially in recent years, earthquakes and human engineering activities have seriously increased geohazard intensity.So far, these unwelcome geohazards have caused great harms to national major projects, regional development, life and property and public safety.This paper firstly presents a general overview of the forming background and development characteristics of geohazards in the Eastern Margin of Tibetan Plateau.Then, the relationship between the geohazard distribution and causative factors was analyzed.Especially the control effect of causative factors on geohazard distribution was discussed through comparatively analyzing the differences of geohazard density of different regions.Finally, sensitivity of the causative factors of geohazards in the eastern margin of Tibetan Plateau was examined in depth.The study results show that nine factors have higher geohazard sensitivity.They are terrain slope, terrain relief, slope shape, annual 24 h maximum precipitation, river density, distance to fault, ground peak acceleration, engineering geological group and human activity intensity.That is to say, they are more prone to geohazard occurrence.However, the slope aspect and annual precipitation have lower geohazard sensitivity and fewer control effect to geohazard occurrence.Moreover, the terrain slope of 25°~40° and terrain relief of 120~160 m·km^-2 have the highest geohazard sensitivity.The geohazard sensitivity of convex slope is higher than that of concave slope.The heavy rainfall with short duration(24 h maximum rainfall) has a higher control effect to geohazard occurrence.With the increase of river density, the geohazard intensity and density shows a corresponding increasing trend.With the decrease of distance to fault or the increase of ground peak acceleration, the geohazard intensity and density all shows an accompanying increasing trend.The study results can deepen the understanding of forming background of geohazards and also provide significant reference for establishing geohazard evaluation index system in the eastern margin of Tibetan Plateau.