| Earthquake landslides are one of the most common secondary geological hazards after earthquakes.Their enormous disaster-causing force often causes great harm to earthquake-stricken areas.Qiaojia County of Yunnan Province,one of the 8.03 Ludian Earthquake-stricken Areas,caused a large number of landslides and geological disasters after the earthquake,resulting in heavy casualties and economic losses.In order to reduce the casualties and property losses caused by landslide geological hazards induced by earthquakes in the future,it is of great practical significance to carry out a comprehensive study on the distribution characteristics and influencing factors of landslides before and after earthquakes,to predict the susceptibility of landslides in disaster areas after earthquakes and to analyze the impact of earthquakes on disaster areas.Taking Qiaojia County as the research area,through field investigation and data collection,to get the basic data of geological hazards,geological environment and geographic elements in the study area.It takes GIS as the technical support platform,combines with existing data,analyses the distribution characteristics of landslides in different influencing factors before and after earthquakes,spatial distribution density characteristics and spatial fractal distribution characteristics,and comprehensively studies the characteristics of landslides before and after earthquakes.The influence degree of different influencing factors of landslide before and after earthquakes is analyzed.The evaluation index of landslide susceptibility before and after earthquakes is constructed.A suitable binary logistic regression model is established to calculate the susceptibility index of landslide occurrence.The spatial probability of landslide occurrence before and after earthquakes is predicted.The zoning maps of landslide susceptibility before and after earthquakes in the study area were made,and the changes of landslide susceptibility before and after earthquakes were comprehensively analyzed,and the influence areas of the earthquake on the study area were obtained.The results show that the influence of elevation and road distance factors on post-earthquake landslides increases,while the influence of stratigraphic lithology,slope,fault distance,water system distance,rainfall and other factors on post-earthquake landslides decreases.the high-impact area of this earthquake is mainly distributed in most areas of Dongping Township,Hongshan Township and Xiaohe Township on both sides of the seismogenic fault,Xindian Township and Baogunao Township near the side of Niulan River,and scattered distribution in Yaoshan Town,Baihetan Town,Laodian Town and Mashu Town.The area of the high-impact area is 424.98Km~2,accounting for 13.33%of the total area of the study area,and the middle-impact area is mainly around the high-impact area,with an area of 937.99 Km~2,accounting for 29.43%of the study area. |
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