A Hazard Assessment Of Geological Disaster In Haicheng City

In recent years,with the needs of economic and social development and the continuous improvement of people's livelihood requirements,the scope of people's activities has gradually expanded,the transformation of natural environment in the process of urbanization leads to various geological disasters,so that people's lives and property have been affected.Based on the detailed investigation project of geological hazards in Haicheng City,Liaoning Province,and taking Haicheng City as the research area,this paper ascertained the development characteristics and distribution rules of geological hazards and the geological environment conditions formed in Haicheng City on the basis of field investigation and data collection,and evaluated the vulnerability of geological hazards in Haicheng City.By using ARCGIS platform,the information model,information model based on AHP and the certainty factor model are used to analyze and compare the results,and the evaluation results of Haicheng geological hazard susceptibility are obtained.The main conclusions are as follows:(1)There are 73 geological disasters in Haicheng,including 47 debris flow disasters,accounting for 64%of the total;15 landslides,accounting for 21%of the total;11 collapsed,accounting for at least 15%of the total.Based on the field investigation and the previous research results,a set of evaluation index system suitable for the Haicheng city is constructed.8 evaluation factors of elevation,slope,slope aspect,distance from river,vegetation index,stratigraphic lithology,average annual rainfall and distance from fault were selected as evaluation indexes of vulnerability.The results show that the geological disasters mainly occur in the southeast hilly area,where lithology is hard or semi-hard rock formations,and near rivers,mainly induced by the heavy rainfall.(2)The geological hazard prone area of Haicheng city can be divided into four levels:the high risk area,the medium-prone area,the low risk area and the non-prone area.Among them,the area of highly prone area is 557.7525 km~2,accounting for 20.42%of the area of the study area;there are 56 hidden geological disasters,and the density of disaster points is0.1004/km~2.The area of the middle prone area is 635.841 km~2,accounting for 23.27%of the area of the study area;and there are 15 potential hazard sites of developing geological disasters,with a hazard density of 0.0236/km~2.The area of the low prone area is 523.9193km~2,accounting for 19.18%of the area of the study area,and there are 2 potential hazard sites of developing geological disasters,with a hazard density of 0.0038/km~2.The non-vulnerable area covers an area of 1014.4872km~2,accounting for 37.13%of the total area,which is the largest area among all the subdivisions.There are no hidden geological hazards in this area.(3)The vulnerability of geological hazards in Haicheng city is evaluated by using information model,information weight model and the certainty factor model.On the basis of the comparative analysis of the evaluation results,the certainty factor model was selected as the final evaluation model,and the geological hazard susceptibility zoning map of Haicheng city was obtained.The results show that the high risk areas are mainly distributed in the low mountain hilly areas of Gushan Town,Jiewen Town and Mafeng Town in the southeast of Haicheng City,and the towns such as Datun Town,Wangshi Town,Chagou Town,Pailou Town,Bali Town and Yingluo Town obviously present the characteristics of banding distribution along the river.The lithology in this area is dominated by granite and hard rock.The average annual rainfall is mostly concentrated in 732?759mm and the altitude is high.The topographic relief is large,the relatively developed joints and fissures,coupled with the influence of heavy rainfall,lead to poor stability of geological bodies,which are prone to geological disasters.The medium-prone areas are concentrated in the periphery of the high vulnerable areas of Ximu Town,Pailou Town and Chagou Town.Low risk areas are scattered sporadically in Haicheng towns.The non-prone areas are mainly distributed in the plain areas with gentle terrain in the north.