关键词: 风险评价, 栅格信息量法, 地面沉降, 主客观组合赋权, 河北省沧州市

Abstract:  Land subsidence risk inducing factors are complex and spatial distribution varies greatly, in order to scientifically carry out land subsidence risk assessment, this paper proposes the raster information quantity method for the evaluation of land subsidence risk. Firstly, the information value between each rasterized evaluation index and surface variables is calculated to quantitatively characterize the strength of the association between the influencing factors and the risk of land subsidence; Then, an evaluation system with 11 indexes is constructed, including hazard, vulnerability, and exposure; Then, the subjective-objective comprehensive weighting method is used to determine the weights and calculate the risk value, and the risk evaluation is carried out through the reliability test of the working characteristic curve of the subjects; Finally, the above methods were applied to the risk evaluation of land subsidence in Cangzhou City, Hebei Province, in 2022. The results show that the raster informativeness values of the hazard and exposure evaluation indicators are high compared to the vulnerability evaluation indicators. Among the hazard evaluation indicators, the annual average land subsidence rate is a high-risk indicator, and when the annual average land subsidence rate is -127--17 mm/a, the informativeness value is 1.538, which is the most hazardous for the risk of land subsidence; Among the exposure evaluation indicators, the population density is a high-risk indicator, and when the population density is >5 430 people/km2, the informativeness value is 1.923, which is the most hazardous for the risk of land subsidence. At 1 km spatial resolution, the area proportions of land subsidence risk levels in Cangzhou City are distributed as follows: 9.90% high risk, 24.91% relatively high risk, 31.12% medium risk, 23.05% relatively low risk, and 11.02% low risk; The high-risk areas were mainly concentrated in the main urban area of Cangzhou City, Suning County, Huanghua City and other areas, and the medium-risk areas were mainly distributed in the western area of Cangzhou City; The reliability of the raster information quantity method to evaluate the risk of land subsidence in Cangzhou City is good, and the accuracy reaches 0.714.

Key words: risk assessment, raster information quantity method, land subsidence, subjective-objective combination assignment, Cangzhou City, Hebei Province