Hazard Assessment Of Landslide In Dechang Based On ArcGIS And SPSS

At present,landslide has become one of the most widespread geological disasters in the world,which seriously damages the natural environment and causes great social and economic losses.Therefore,to study the development of regional landslides and make a reasonable evaluation will help to weaken its negative effects.Due to the influence of more than ten years of earthquakes,frequent extreme weather and irrational human engineering activities in Southwest China,the geological environment in mountainous areas of Sichuan Province is becoming more and more unstable,and the incidence of geological disasters is increasing in recent years.Dechang County has always been one of the districts and counties with serious geological disasters in Sichuan Province.Especially after the earthquake and influenced by the recent frequent extreme weather,the frequency,quantity and scale of landslides in the county have increased dramatically,causing certain economic and property losses every year,which has become an important factor affecting the economic development and social stability of the county.The important traffic trunk lines in Southwest China,such as Chengdu Kunming railway,Beijing Kunming Expressway and national highway 108,pass through Dechang County,which are threatened by landslides in varying degrees.Moreover,the occurrence of disasters has a chain effect,and the probability of debris flow following the landslide is quite high.The superposition effect of multi gully group landslide debris flow disaster induced by rainstorm in Dechang County usually leads to more serious disasters^[5-7].Based on this analysis of the landslide disaster in Dechang County,scientific prediction of the risk area of landslide and timely prevention and control are of great practical significance for the protection of landslide risk in the county.Based on the statistics and arrangement of the landslide disasters in Dechang County,the environmental geological conditions in the study area are analyzed,the mechanism of landslide occurrence is analyzed,the influencing factors closely related to landslide are selected,the appropriate landslide risk assessment model is established,the landslide risk zoning in Dechang County is carried out,and the zoning results are evaluated.?1?Based on the field investigation and remote sensing interpretation data analysis of Dechang County,the development and distribution characteristics of land-slides and geological environment conditions of disaster pregnancy are preliminar-ily obtained.Combined with correlation analysis,the evaluation factors of landslides in the study area are screened,and the evaluation index system of landslide risk in Dechang County is constructed.?2?Based on the support of ArcGIS and SPSS software technology,four kinds of evaluation models are used to evaluate the landslide risk in Dechang County.By comparing the corresponding results of four different evaluation models,the ROC curve and AUC value are used to verify the accuracy,and the accuracy and applicabi-lity of several methods are obtained Thus,the most accurate landslide risk zoning map can be obtained.?3?The AUC value of the ROC curve of the I+LR model is the highest,which is0.862.It shows that the coupling model of information quantity and logic regressi-on is the best and the most accurate for the evaluation of landslide risk in Dechang County.According to the results of the I+LR model,the landslide risk in Dechang County is classified into five levels:extremely high,high,medium,light and very light.There are 215 landslides in Dechang County,including 151 extremely high and highly dangerous areas,accounting for 70.24%.Further surface classification results are ideal.The area of moderate and above landslide risk areas is 1061.84km².It can be seen that the regional landslide risk in Dechang County is relatively high,showing the characteristics of centralized distribution,and the occurrence of landslide disasters in the area of slight and below is scattered and less.