| Longyan city is a typical karst basin, its main water comes from underground karst water. Pumping will affect the water table, which induces karst collapse. Population concentrates in urban areas, karst collapse is a tremendous risk for production and life of people. Therefore, this research focuses on how to assess the region's karst collapse risk more effectively. It will produce great social significance. In this paper, we collect a large number of regional hydrogeological engineering geological data and estabilish database by analysis and sorting. The main job is the following two aspects:The first part is risk assessment of karst collapse.Groundwater depth, water-rock distance, karst type, soil thickness, soil stucture, linear karstification rate, geological structure, hydraulic connection and pumping well are selected as 9 factors through collecting geological background of Longyan city and field investigation. According to different accuracy of thematic map, point files are interpolated into zone files separately by voronoi, IDW, ordinary Kriging and indicator Kriging interpolation methods. GIS spatial analyst is used to assess karst collapse risk. And the paper firstly attempts to take a combination of information quantity and AHP as the evaluation model. When making comparisons between the two, AHP is often based on their own subjective assessment and different people will give different weights. While information quantity method takes into account of the impact coming from combination of different factors. AHP subjective arbitrariness can be made up by the use of information quantity method. On the basis of information quantity, the weights of AHP criteria are determined and overlay analysis of ArcGIS is used to make a reasonable prediction. Most sinkhole points fall into high-risk areas, which shows this method can achieve the purpose of assessment.Through the results, we can find that the greatest risk area of Longyan basin concentrated in Xicheng district and Dongxing village, Donggongxia village of Dongcheng district and Dayang village, Xiaoyang village of Xipi town and Dongshan village, Caoxi town. And 2.7% of the total area is very easily collapsed; The region where is more prone to collapse compared to 8.8%; Stable region make a ratio of 15.7%; Most area is more stabler region and the middle-prone areas, accounting for 46.9% and 25.9%. Distance between water level and the bedrock surface and pumping activities make greater affect on karst collapse than others. The weights of these factors are relatively higher.The second one is initial study of the insurance for pumping karst collapse.Sinkhole caused by pumping is man-made disaster. According to《Prevention and Control of Geological Disasters Regulation》:a person who caused geohazard should be charged of this damage. This article try to propose insurance risk assessment indexes of pumping karst collapse referencing to sinkhole insurance system of Florida, the United States:Risk index PI is based on probability of sinkhole occurrence, it can be calculated by the occurrence probability of karst collapse in different risk zoning; The other index is QI, which can quantify the value of pumping losses. We can decide sphere of influence and divide different strength zones of the pumping well according to its exploitation number of groundwater. About the disaster bodies, housings, roads, underground pipelines and indirect losses of three major industries are took as main evaluation indicators. Disaster management costs investigated is the standard for damage assessment. And QI is obtained through quantitative assessment of economic loss within the sphere of influence.After the two indexes are determined, we can calculate expected loss value, and next we can calculate premium. This article is intended to formulate an idea of insurance for pumping karst collapse, and also wants to give a reference for insurance used for compensation of karst collapse man-made in the future.
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