Research Of Geological Disaster Liability Assessment In Ludian Earthquake Disaster Area

This 6.5 magnitude earthquake in Ludian is a kind of strike-slip type. It is happened near north east Xiyu river-zhaotong fracture. Mountainous area ratio is high in the disaster area. Geological structure is comples,also the new tectonic movement is active.So multiple faults developed and rock mass broken.When there is a heavy rainfall,it will induce a large number of sec-geological disasters,for example,debris flow,landslide,collapsion and so on.The thesis is based on detailed investigation of Remote sensing and Geological Interpretation in Prone to Disaster Areas.The thesis study the development characteristics,formaion mechanism and distribution of geological disaster in detail in the quake-kit region,based on regional geolonal data collected widely. Through the method of combination of the AHP model with ARCGIS,we make zonation of the geological hazard susceptibility area.Through these studies,the major progress and conclusion are obtained in this thesis as follows:1)we preliminary reveal the characteristics and regularity of distribution of geological disasters in earthquake disater area.The first three geological disater type is landslid,debris flow and collapsion.The geohzards distribute mostely at Jintang,Dazhai,Menggu in Qiaojia county and Longtoushan,Suoshan in Ludian county.In macro point of view,the geohazards distribute on the North-South fault belts along the both sides of Jinsha river and Niulan river.The geohazards in study area are formed main in the limestone and shale zone.2)we get the main control and induce factors of the geological disasters in the earthquake disaster area.The main control factors are elevation,slope,formation lithology,fault belt,river and road system,vegetation coverage,and so on.The firist induce factor are earthquake.3)we interpretate the sec-geological disasters in Ludian earthquake disaster area for the first time.According to the result of interpretation,we can conclusion that the geohzards triggered by the earthquake focused on the epicenter-Longtoushan town along the Niulan river.It fits the result of risk assessment.And it also reflect the good capability in geological disaster investigation of GF-1.4)we make zonation of the geological hazard susceptibility and dangerous area using the method of the AHP model,combined with ARCGIS.Based on analysis the features and factors of the geological disaters,we build up the evaluation system of susceptibility and determine the weight of each index according to expert evaluation method.Based on the spatial analysis function of ARCGIS platform,we grade and assign each evaluation factor and build up the index model of susceptibility.We calculate the value of each factors through GIS on computer, superpose the induce factor of earthquake intensity. Based on this,we and obtain the susceptibility zonation of geohazards, which is classified in four division. The four divisions are high liability division, moderateliability division, low liability division and zero liability division.Finally,we can divide the disaster prevention and control division.