基于信息量与逻辑回归模型的次生滑坡灾害敏感性评价——以汶川县北部为例

Susceptibility assessment of secondary landslides triggered by earthquakes:A case study of northern Wenchuan

次生滑坡灾害的影响是震后较长时间里人们持续关注的焦点,对其开展敏感性评价具有重要意义。选取5.12地震的重灾区汶川县北部作为研究区,利用遥感与地理信息技术提取地震滑坡信息,在全面分析滑坡与高程、坡度、坡向、岩性、断裂带、地震烈度以及水系等7个影响因子相关特性的基础上,采用信息量法与逻辑回归模型进行灾害敏感性评价,将研究区划分为极轻度、轻度、中度、高度和极高危险5个级别,并对不同模型的适用性开展分析和对比。结果表明,逻辑回归模型在描述区域滑坡灾害危险度总体特征方面稍具优势。

The Ms 8.0 Wenchuan earthquake,which occurred on 12 May 2008 in Sichuan Province,collapsed a great many houses and injured thousands of people.Undoubtedly,it can be predicted that secondary earthquake landslides,as a common secondary hazard triggered by earthquakes,will draw much attention during a long time after earthquake due to the severe geological hazard.In order to remove threat from the secondary disasters effectively,this study used remote sensing and GIS to generate susceptibility maps,taking the case of northern Wenchuan County.Seven factors affecting landslide occurrence have been taken into account in the susceptibility assessment,including elevation,slope,aspect,lithology,seismic intensity,distance to faults and rivers.According to the probability that predicts the possibility of landslide occurrence by information value method and logistic regression separately,the study area was ultimately categorized into five classes,namely,＂extremely low＂,＂low＂,＂moderate＂,＂high＂ and ＂very high＂.The result has proved to reflect closely the spatial distributions of landslides in the study area.Subsequently,these two probabilistic and statistical approaches for estimating the susceptible areas of the study area of Wenchuan County were tested.It can be concluded that the predictive capability of logistic regression model appears to be more accurate compared to information value method.It is mainly due to the fact that logistic regression could reduce effectively the subjectivity in selection of evaluation factors and weight assignment.