Characteristics of geological hazards and it’s mitigations of the Ms6.8 earthquake in Luding County, Sichuan Province

On September 5th, 2022, the Ms 6.8 earthquake in Luding County, Sichuan Province induced large numbers of geological hazards. In order to deeply understand the evolution, distribution, and characteristics of geological hazards caused by the earthquake, we obtained the distribution of geological hazards by the field investigation and remote sensing interpretation. The conditions for hazard control and the countermeasures for hazard prevention and reduction are also analyzed. The results show that as of 22:00 on September 14, 2022, the earthquake has induced 565 geological hazards with threat objects in Luding County and Shimian County (including 331 collapses and 234 landslides), and 81 existing geological hazards whose deformation increased. The geological hazards induced by the earthquake are mainly medium and small mass high-level collapses, which are mainly concentrated in the areas with Seismic intensity zone of Ⅸ near the epicenter. These areas include Moxi Town, Detuo Township, both banks of Dadu River between Detuo Township and Dewei town in Luding County, Caoke Township and Wanggangping Township in Shimian County. According to the experience of the Wenchuan earthquake, the debris flow will be active in the next five years, and its characteristics of high frequency and viscous debris flow should be considered in the design of debris flow prevention and control engineering. Under the rainfall condition, the landslide deposition remaining on the slopes of Dadu River banks in the section of Detuo Township—Dewei Town can easily transform into debris flow. The transformation forms of the two hazards’ types should be fully considered in the design of prevention and control projects. The study can provide a reference for earthquake geological hazard prevention and post hazard reconstruction planning in the earthquake area.