基于"国土空间人地关系"视角的人口分布地质灾害人口暴露度分析——以湖南省为例OA

The accurate identification of population exposure to geological hazards is an important prerequisite for disaster risk prevention and territorial governance.In published studies in the literature,the main focus was on the assessment of susceptibility to geological hazards,whereas the spatial coupling of fine-scale population distribution,population vulnerability,and territorial planning has received relatively limited attention.Based on the theoretical perspective of human-environment relationships in territorial planning,a grid-county dual-scale assessment framework was constructed in this study to evaluate population exposure to geological hazards.Taking Hunan Province,China,as the study area,we first used Baidu Huiyan population big data calibrated with county-level data from the Seventh National Population Census to characterize the 1-km-gridded population distribution.Then,using the landform,slope,precipitation,NDVI,land use,distance to rivers,distance to roads,lithology,and distance to faults as factors,a random forest model was trained to assess the susceptibility to geological hazards.On this basis,a Population Exposure Index for geological hazards was constructed using a population-weighted spatial overlay,and county-level exposure patterns were further analyzed in relation to population vulnerability and territorial spatial planning units.The results showed that the population of Hunan Province is distributed in an"east-high,west-low,core-outward"pattern.Areas with a high population density are mainly concentrated in the Changsha-Zhuzhou-Xiangtan urban agglomeration and extend toward the Dongting Lake Plain and central Hunan Basin,whereas the western and southern mountainous areas are characterized by a relatively low population density.However,the population vulnerability is not fully consistent with the population density.Some mountainous and hilly areas have a relatively low population density but high social vulnerability,indicating that the social basis of disaster risk is spatially uneven.The results of the geological hazard susceptibility analysis showed a clear pattern of"high in mountainous and hilly areas and low in plains and urban areas."Areas with high susceptibility are mainly distributed along the Wuling,Xuefeng,and Nanling mountain ranges,whereas those with relatively low susceptibility include the Dongting Lake Plain and Changsha-Zhuzhou-Xiangtan urban region.The county-level Population Exposure Index further revealed a spatial pattern different to that of population density alone.Overall,population exposure is higher in mountainous areas and lower in plains,suggesting that geological hazard exposure is not simply determined by population concentration but is the result of the spatial overlay between population distribution and geological hazard susceptibility.Although the Changsha-Zhuzhou-Xiangtan urban agglomeration and Dongting Lake Plain are densely populated,their exposure levels are relatively limited because of their lower susceptibility to geological hazards.By contrast,although parts of western and southern Hunan have smaller populations,settlements are often located in valleys,piedmont zones,and other local areas with higher susceptibility to hazards,resulting in higher population exposure.Additionally,the analysis of the main functional zones revealed differentiated exposure structures.National key ecological function zones showed the highest and relatively stable exposure levels,whereas provincial urbanization areas showed stronger internal variation despite also showing relatively high exposure levels.After controlling for natural background conditions such as elevation,slope,landform,and lithology,the main functional zone types still showed significant explanatory power for the Population Exposure Index,indicating that exposure differences across functional zones cannot be fully explained by natural conditions alone and may also be related to territorial development patterns and functional zoning arrangements.This study extends the assessment of geological hazard susceptibility from the identification of hazardous environments to the evaluation of population exposure and vulnerability-informed risk representation.It also links gridded exposure measurements with county-level territorial spatial governance units,thereby improving the applicability of exposure assessments to territorial spatial planning.These findings provide quantitative support for identifying priority governance units,improving geological hazard prevention,and promoting differentiated territorial spatial management.