中国地质环境脆弱性评价

Evaluation Research on the Fragility of Geological Environment in China

中国地质环境具有先天脆弱性,空间分布存在巨大差异,对于区域生产力布局、工程建设、国土空间开发等社会经济诸多方面具有很大的影响。本研究基于ArcGIS平台,采用层次分析法构建包含地质构造、地表形态、组成物质三大类9个一级指标的地质环境脆弱性评价指标体系;将地壳稳定性、断裂带分布、海拔高度等9个脆弱性指标图层进行线性变换归一化处理,得到各指标标准值图层;运用因子相关分析法,分析9个脆弱性指标间相关性;应用主成分分析法,将相关性显著重复的要素删去,重新组合成一组新的互相无关的综合脆弱性要素;以主成分要素对应的方差贡献率作为权重,应用综合指数模型,完成地质环境脆弱性综合评价;在区位理论及空间统计的支持下进行进行分区,将全国划分为微度、轻微度、轻度、中度、重度和极度等6类脆弱区;综合分析中国地质环境脆弱性分布的空间特征及区域差异。研究结果表明,总体脆弱是中国地质环境的突出特征,中度至极度脆弱区面积约占中国全国土地面积的1/3,这是中国国土空间开发所面临的自然基础条件;中国区域地质环境脆弱程度呈现西北高东南低、西南高东北低且镶嵌式分布的总体空间格局,大致以贺兰山-六盘山-邛崃山-乌蒙山一线为界,此线以西地区地质环境脆弱程度高,此线以东地区地质环境脆弱程度低。

China’s geological environment is fragile fundamentally and has great spatial variance,which greatly affects the socioeconomic development,such as regional allocation of productive force,engineering construction and regional territorial development.Based on the ArcGIS platform,an index system has been developed for the fragility evaluation of regional geological environment,which includes geological structure,earth surface landform and material composition with 9 first level indicators.After carrying out the Min-Max normalization of nine fragility indicators such as the crustal stability,the distribution of fracture zone and elevation,the maps of standard values of all indicators have been obtained in this paper.The correlation among nine fragility indicators has been analyzed by factor correlation analysis.The repetitive elements with significant correlation have been removed based on the principal component analysis,and then a new set of elements on comprehensive fragility has been developed.Taking the mean square deviation contribution rates corresponded to principle component as the weights,the comprehensive index model has been applied to make a comprehensive fragility evaluation of geological environment.Furthermore,with the support of location theory and the GIS spatial statistical analysis,the fragility of China’s geological environment has been quantitatively classified into six zones:minor,gentle moderate,moderate,medium,severe,extreme fragile.And then,the spatial characteristics and regional difference about the fragility distribution of China’s geological environment have been analyzed comprehensively.The results show that overall fragile is a prominent feature of China’s geological environment,and the areas of moderately fragile and extremely fragile zones in China take up appropriately one third of the national terrestrial area.This is also the natural basic condition faced by China’s national development and resource exploitation.The overall spatial pattern about the fragile degree of China’s regional geological environment shows that the northwest is higher than the southeast,while the southwest is higher than the northeast,besides a little mosaic distribution.Taking the Helan Mountain–Liupan Mountain– Qionglai Mountain–Wumeng Mountain as an approximately boundary,it’s found that the fragility of the geological environment in west is high,but the ones in east is low.