基于加权证据权模型的青藏高原东部巴塘断裂带滑坡易发性评价

巴塘断裂带位于青藏高原东部,呈北东—南西向展布,全新世活动强烈,沿断裂带崩塌、滑坡、泥石流等地质灾害极为发育。基于遥感解译和野外地质调查,在巴塘断裂带两侧10 km范围内识别出滑坡93处;在分析滑坡空间发育特征的基础上,选取地形地貌(地面高程、地形坡度和地形坡向)、地形湿度指数、地层岩性、活动断裂、降雨量、水系、人类工程活动和植被覆盖等10个因素作为滑坡易发程度的主控因素,采用加权证据权法建立滑坡易发性评价模型,开展巴塘断裂带滑坡易发性评价;成功率(ROC)曲线检验结果表明此次滑坡易发性评价的准确率为82.3%。采用基于自然断点法将滑坡易发程度划分为极高易发、高易发、中等易发和低易发4个级别,结果表明滑坡易发性受巴塘断裂带和河流控制显著,极高易发区和高易发区主要分布在巴塘断裂带、金沙江和巴曲河谷及一级支流两侧,中等易发区主要分布在巴曲各支流中上游,低易发区主要分布在人类工程活动弱的高山地带以及地形相对平缓的区域。滑坡易发性评价结果很好地反映了巴塘断裂带现今滑坡发育分布特征,对该区重大工程规划建设和防灾减灾具有科学指导意义。

Landslide Susceptibility Assessment Based on Weight-of-Evidence Modeling of the Batang Fault Zone,Eastern Tibetan Plateau

The NE-SW-trending Batang fault is located in the eastern Tibetan Plateau,and has strong Holocene activity.Geological disasters such as collapses,landslides,and debris flows along the Batang fault zone are common.Through remote sensing interpretation and field survey,we established a landslide inventory over 10 km from both sides of the Batang fault,and a total of 93 landslide hazard points were identified.Based on the landslide geological background analysis,we summarized ten landslide susceptibility evaluation factors,i.e.,topography(elevation,slope,aspect),topographic wetness index,lithology,meteorology and hydrology,active faults,engineering activities,and vegetation coverage.Weight-of-Evidence Modeling is used to calculate the landslide susceptibility.Using the receiver operating characteristic(ROC)curve accuracy of 82.3%,and the natural breaks-based method,the landslide susceptibility along the Batang active fault zone is divided into four levels(extremely high,high,medium,and low).The landslide susceptibility is mainly controlled by the Batang fault and river valley.The extremely high and high susceptibility zones are mainly distributed along the Batang fault zone and along the Jinshajiang and the Baquhe river valleys.The medium susceptibility zones are mainly distributed on both sides of the Baquhe tributaries.Low susceptibility zones are mainly distributed in high mountain areas with low engineering activities,and in relatively flat topography.The landslide susceptibility analysis results can well reflect the landslide development features along the Batang fault zone,and can provide scientific support for the major project construction and disaster prevention and mitigation.