The development characteristics of geological hazards in Gansu segment of the Yellow River basin

Gansu section of the Yellow River basin is the most concentrated area of geological disasters in Gansu Province. By the end of 2019, 12829 potential geological hazard points have been identified, accounting for 70.83% of the total number of disasters in Gansu Province. According to the distribution characteristics of water system, Weihe River basin, Jinghe River basin and the Yellow River basin are the most developed, followed by other water systems. According to the spatial distribution characteristics, it can be divided into three sections: the northern Yongdeng—Jingyuan debris flow area, the central and northern landslide debris flow concentrated section, the central and southern collapse landslide debris flow section, and the southern Maqu—Luqu geological disaster development section. In terms of time distribution, there are two high frequency periods: freezing and thawing period from February to May and main flood season from July to September. Geological disasters have the characteristics of small disaster and huge loss, mass damage and chain type huge loss. Single disaster is easy to form huge loss. The mass geological disaster caused by rainfall and earthquake often causes huge loss. At the same time, the risk of dammed lake formed by landslide flow blocking river channel often occurs.