Sliding process and causative mechanism of the Zhongchuan landslide-mudflow disaster chain induced by the 2023 Jishishan Ms6.2 earthquake
On December 18,2023,an Ms6.2 earthquake occurred in Jishishan County,Gansu Prov-ince.This earthquake triggered a severe mudflow disaster in Zhongchuan Township,Minhe Coun-ty,Qinghai Province.Based on the detailed on-site investigation,low-altitude photogrammetry,en-gineering geology mapping,and soil water content experiments,fundamental characteristics,dy-namic development,as well as causative factors of the landslide disaster were investigated and an-alyzed.The results suggest that the landslide initiated in a phased and block-wise manner,demon-strating a progressively retreating slip pattern.The analysis suggests that the landslide was pre-dominantly attributed to such composite factors:prolonged irrigation activities undertaken by lo-cal inhabitants culminated in the establishment of saturated loess layers beneath the surface;sub-sequent to the strong earthquake shaking,the pore water pressure within these saturated loess layers experienced a rapid escalation,inducing a state of liquefaction in the loess.This liquefied state prompted the swift descent of the saturated loess,bearing the overlying unsaturated soil lay-ers,towards the gullies.Additionally,the landslide mass mixed with continuously and irrigation canals underground,further intensifying the formation of the landslide-debris flow disaster.The study area is surrounded by similar irrigation regions;therefore,the prevention and management of such landslides under future seismic conditions is very crucial.
Jishishan earthquakeloess liquefactionlandslide-mudflow disaster chainirrigationsliding process
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