The Assessment Of Risk Of The Ground Fissures Based On GIS In Weihe River Basin

In recent years,as an phenomenon of surface geological disasters,the ground fissures in the world are found in many countries,especially in some big and economically developed cities which have lots of people,and its frequency and situation of the disaster is aggravated year by year.As one of the major geological disasters,the number of ground fissures which varies scale and vary origin in the Weihe River basin are 191,the ground fissures have caused serious economic losses and do harm to the city and the construction of municipal facilities,housing for rural residents,as well as irrigation of arable land. Therefore,we must carry out the research work of the ground fissures of disaster assessment,prediction and prevention.In this paper,the State of geological Investigation requested Chang'an University that. "the ground fissures of western region and the ground investigation".My paper use the research results of the ground fissures of Weihe River Basin project(1:10000).First of all, the study area of geo-environmental background has been analyzed and the causes,classification and characteristics of the ground fissures in the Weihe River Basin,and then we use ArcGIS software as a platform to establish a spatial database and carry out the fuzzy comprehensive evaluation method to appraise the danger of the ground fissures disaster, then we use the 300m * 300m evaluation unit,and ultimately we get the danger of the ground fissures partition map which is matched with the actual status of the investigation. The main results of this study in my paper are:(1) An analysis of the ground fissures disaster to the environment and the development of physical geography topography,lithology,hydrogeology,the new tectonic movement and seismic and other geological environmental background;(2) An analysis of the distribution and characteristics of the ground fissures with the morphological characteristics,causes,classification and analysis of hazards;(3) To set the ground fissures index system of risk assessment,select an evaluation factor,according to the characteristics of the evaluation model to select a reasonable method to quantify the indicators and the use of AHP to determine weights of the indicators;(4) As a platform for all ArcGIS layers of graphics information and attribute information for the collection,the study area was established to crack disaster spatial database,a query analysis,overlay analysis and buffer analysis,spatial analysis function; identified research the ground fissures in disaster areas to mathematical model of risk assessment(multi-level fuzzy comprehensive evaluation method);(5) The use of grid computing to generate a superposition of the study area to the extent of cracks in hazard zoning map of the study area and it will be divided into mild(â… ), moderate(â…¡),high(â…¢) and high(â…£) in four level,the results show that the ground fissures in the highest hazard areas are mainly distributed in Dali County,jingyang County, Sanyuan County,and Xi'an city,with an area of about 3555.09km~2,accounting for 12.5%of the total area;highly dangerous area of about 2940.12km~2,accounting for 10.4 percent of the total area;the risk of moderate area of about 9390.42km~2,accounting for 33.0 percent of the total area;dangerous area mild about 12521.16km~2,accounting for 44.1 percent of the total area.