基于因子相关性-聚类分析的巴谢河流域滑坡危险性评价

Assessment of Hazard of Landslide in the Baxie River Basin Based on Factor Correlativity-Cluster Analysis

巴谢河流域是甘肃省东部滑坡高易发区域,滑坡活动频繁。基于遥感解译与野外调查,分析了地形地貌因子、地层岩性、植被覆盖、人类工程活动等因子对流域内滑坡的相关性。结果表明:滑坡分布与地形地貌关系密切,高程2 000~2 200m、坡度15°~40°、阳坡坡向及沟谷密度1~2.5km/km^2的范围内,滑坡尤为发育;滑坡与地层岩性、植被、人类活动等也有较好的对应关系,其中岩性为马兰黄土及泥岩、NDVI在0.2~0.3与距离道路600m的范围内滑坡易于发生。依据各因子与滑坡的相关性对其进行聚类分析,将整个研究区域分4个危险区:高、中、低和极低危险区,所占研究区面积比例分别为30.9%,21.7%,30.3%,17.1%。

Baxie River Basin is the area where the landslides frequently occur in the eastern part of Gansu Province.Based on the field investigation and remote sensing interpretation,the influential factors on landslides were analyzed.The results indicate that the distribution of landslides is closely related to the landform and physiognomy,presenting a high concentration in the ranges of elevation of 2 000~2 200 m,slope gradients of 15°~40°,relief amplitude of 100~200 m,sunny slope,cutting depth of 50~100 m and gully density of 1~2.5 km/km^2.In addition,the distribution of landslides is well correlated with the lithology,vegetation cover and human activities,especially with the lithology of Malan loess and mudstone,Normalized Difference Vegetation Index of 0.2~0.3 and scopes of 0~600 m distance from the roads.According to the correlation between each factor and landslide,the cluster analysis is carried out to divide the study area into four dangerous areas:high danger zone(accounting for 30.9%of whole area),moderate danger zone(accounting for 21.7%of whole area),low danger zone(accounting for 30.3%of whole area),and extremely low danger zone(accounting for 17.1%of whole area),respectively.