Causes and destructive analysis of the liquefied mudflow in Zhongchuan Town triggered by the 2023 Jishishan,Gansu Ms6.2 earthquake
At 23:59 on December 18,2023,an Ms6.2 earthquake struck Jishishan County,Linxia Prefecture,Gansu Province,triggering several geological disasters.One of the most severe was a sand-soil liquefied mudflow disaster in Zhongchuan Town,which caused significant economic los-ses and casualties.It is crucial to analyze its characteristics,causes,and destructiveness.Using existing references and high-precision,high-resolution digital data,we conducted a comprehen-sive post-earthquake mudflow analysis through image interpretation and ground investigation.The results showed the following:(1)The saturated and slippery loess experienced a rapid in-crease in pore water pressure owing to seismic load,leading to sand-soil liquefaction.This desta-bilized and destroyed the soil layer,causing the collapse of the plateau's edge and triggering seis-mic landslides.The soil-water mixture then flowed down the slopes and valleys under the influ-ence of gravity,forming a liquefaction-type landslide-mudflow disaster.(2)The disaster was not a single mudflow event but a simultaneous occurrence of mudflow and sand gushing caused by sand liquefaction.This dual action is extremely rare and highly destructive.(3)Despite its mod-erate magnitude,this earthquake exemplifies the"small and medium quake,large disaster"sce-nario.It caused greater destruction and casualties compared to similar-scale earthquakes,high-lighting its particularity and abnormality.
Jishishan Ms6.2 earthquakecause of liquefied mudflowdestructive analysissand gushing
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