Distribution And Susceptibility Assessment Of Geological Hazards In Mahuangshan, Yanchi Country, Ningxia Province

Yanchi Country is one of the geological disaster prone areas of NingxiaProvince.The geological disasters of Yanchi Country concentrated in Mahuangshanarea,the south of the country.The types of geological disasters which have been foundare landslide,collapse and debris flow.And all those geological disasters have causedharm and losses to the local people.In this paper, on the basis of detailed geologicaldisaster survey,Geological Information System(GIS) has been used to get thegeo-hazard susceptibility zoning map of Mahuangshan area,eventually makingreasonable predictions on disaster tendency.The specific research content as follows:(1) Preliminary summarized the background conditions of the geological disasterformation.The spatial distribution of geological disasters of Yanchi Country reflectsregional concentration.Landslides,collapses and mudslides mainly concentrated in theMahuangshan,in the south of Yanchi country,in which lithology mainly are loess,clayand loess-like sub-soil,which have poor mechanical properties.Meanwhile,thetopography of the region also has a great impact on geological disaster formation.(2) Preliminary revealed the types of geological disaster, the regulation ofdisaster development and the regulation of disaster distribution.Geological disasters inMahuangshan are mostly landslides,collapses,and a small amount of debrisflows.Landslides are mainly small-scale retrogressive loess landslides.Collapses aremainly small-scale toppling soil landfall.Debris flows are mainly mudslides.Theregulations as follows:①The geological disasters have regionalconcentration,unexpectable occurrence and small scale.②Disasters are widelydistributed in the loess hilly region.③Disaster spatial distribution is influenced by theravines as well as the surface flows,with a clear zonation along the ravines andconcentration in river basin.④The occurrence of disasters is consisted with the timeof rainfall.(3) Geo-hazard susceptibility assessment and susceptibility zoning map ofMahuangshan.Make use of information model combined with ArcGIS to get the geo-hazard susceptibility zoning map of the study area.In accordance with the degreeof geo-hazard susceptibility,the study area is divided into subareas:The subareas withhigh susceptibility are widely distributed in Mahuangshan.The subareas with mediumsusceptibility are mainly on edge of high susceptibility areas and some scattered inhigh susceptibility areas.The subareas with low or very low susceptibility are mainlyin the northern fringe of study area.Overall,the Mahuangshan area is high geo-hazardsusceptibility region.