Landslide Hazards along River Corridors - Landslide outline (polygon contains all features of a deep-seated landslide)

Where fluvial or coastal erosion has created steep, high slopes in glacial sediments, these slopes sometimes fail in large, deep-seated landslides. The segregation of landslides into deep and shallow is somewhat arbitrary and different investigators have used different criteria to differentiate these landslides. For this project, the differentiation follows the criteria proposed by Burns and Madin (2009) that deep-seated slides extend to a depth of more than 15 ft. (4.6 m.). In general this corresponds to individual landslides which are large enough to be distinct on hillshade images generated from LiDAR data. For this mapping, deep-seated landslides may include features where the failure plane is more than 15 ft. deep or where landslide debris accumulates to a depth of more than 15 ft. In King County, a variety of landslide types occur at a scale that may create deep-seated landslides.当河流或海岸侵蚀在冰碛物中形成陡峭高陡边坡时，此类边坡有时会发生大规模深层滑坡（deep-seated landslides）。将滑坡划分为深层与浅层的方式具有一定主观性，不同研究者采用了不同的判别标准来区分此类滑坡。本项目采用Burns与Madin（2009）提出的判别标准，将深层滑坡定义为滑深超过15英尺（4.6米）的滑坡。一般而言，此类滑坡规模足够大，在由激光雷达（LiDAR）数据生成的山体阴影图（hillshade images）上可清晰辨识。在本次制图工作中，深层滑坡可涵盖滑面深度超过15英尺，或滑坡堆积物厚度超过15英尺的滑坡体。金县（King County）境内存在多种滑坡类型，其发育规模可形成深层滑坡。