Inventory Mapping of Landslides using Lidar in the Buffalo National River, Arkansas

LiDAR has become a powerful tool in investigating and mapping topography and anomalous landforms, such as landslides. High-resolution LiDAR can indicate many distinctive physical features of landslides, such as crown, main and minor scarps, hummocky topography divergent contours. The combination of manually mapping using contour patterns on topographic maps with hillshaded images derived from digital elevation models (DEMs), can result in more accurate estimates of mass wasting, depending on the resolution of the LiDAR data. The major emphasis of this study is centered on the use of Airborne LiDAR, topographic maps and satellite imagery to differentiate mass movements of various types along Buffalo National River in Arkansas. The horizontal resolution of the LiDAR data was one meter. Standard LAS files from LiDAR were processed to create DEMs, slope maps, and hillshaded images. The ground classification points from LiDAR were used to create bare-earth hillshaded images. These information layers constituted the primary data set used for visualization and landslide mapping. The LAS files were imported into GIS software (ArcMap and QGIS) to create the hillshaded bare-earth DEMs. Other data sets included topographic contours (5- and 10-ft intervals), high-resolution color aerial photography, and 1:24,000-scale geologic and topographic maps and previous landslide inventories from the Arkansas Geological Survey (AGS). The preliminary results detected various types of landslide features, which vary along the river. Some of the landslides were previously unrecognized, while other features, like scarps, were newly recognized and allowed more precise information to classify the type of mass wasting (e.g. flows slides versus block glide translational slides). The use of the high-resolution airborne LiDAR allows for much greater spatial resolution in identifying bedrock landslide features, especially in rolling forested terrain