面向地质灾害防治的第四系空间信息提取研究

第四系空间分布及其厚度信息提取是地质灾害防治工作中的关键技术之一。以三峡库首区秭归段为研究区,在收集遥感影像、地质图、地形图以及勘查资料等多源数据的基础上,分析了第四系空间分布及其堆积厚度的影响因素,确定地层岩性、坡度、水系多级缓冲区、归一化植被指数(NDVI)以及遥感影像光谱特征中的亮度(Brightness)和遥感影像纹理特征中的灰度共生矩阵对比度(GLCM contrast)作为第四系空间信息提取的评价因子,并利用C5.0决策树构建了第四系空间分布及其相对厚度信息提取模型,编绘了研究区第四系相对厚度空间分布图。结果表明:区域内第四系的空间分布及其堆积厚度由岩性和水系控制,而局部主要由坡度控制;遥感影像的光谱、纹理特征较为真实地反映了第四系的空间分布信息;172 m高水位蓄水期间的塌岸调查结果佐证了第四系厚层区划结果的可信度,该研究结果在水库蓄水后库岸再造或塌岸防治方面具有一定的参考价值。

Research on Quaternary Spatial Information Extraction for Prevention and Control of Geological Hazards

The information extraction of Quaternary spatial distribution and its thickness is one of the key techniques in the prevention and control of geological hazards.Taking Zigui section in the Three Gorges Reservoir Area as the research area,this paper analyzes the influencing factors of Quaternary distribution and accumulation thickness on the basis of collecting multi-source data such as remote sensing images,geological maps,topographic maps and field investigation information.The paper determines lithology,slope,distance from drainage,NDVI,brightness and GLCM contrast as information extraction estimating factors,and applies C5.0 decision tree to constructing the Quaternary spatial distribution and relative thickness information extraction model and mapping Quaternary relative thickness of the study area.The results show that Quaternary spatial distribution and its thickness is controlled by lithology and distance from drainage in regional,it is also controlled by local slope;the spectral and texture features of remote sensing images reflect the spatial information of Quaternary;the results of the bank collapse survey during the 172 m high water storage period corroborate the credibility of the Quaternary thick layer zoning results.The research content has certain reference value in reservoir rebuilding or bank collapse prevention after reservoir water storage.