PATTERNS IN LANDSLIDE PROCESSES ACROSS APPALACHIA'S DISTINCT LITHOTECTONIC PROVINCES: INSIGHTS FROM QL1 LIDAR-DERIVED IMAGERY

The study of slope movement history in central and southern Appalachia is complicated by extensive forest cover that frequently obscures physical evidence of slope failures older than a few decades. Recently acquired QL1, 1-meter or finer-resolution lidar datasets now allow detailed evaluation of slope movement history throughout rugged Appalachia, regardless of modern-day ground cover. Landslide inventories supported by QL1-derived lidar imagery can provide a more accurate representation of slope movement style, density, and mobility. To some extent, relative age of slides can be estimated based on the deterioration of slide-related features observed in lidar-derived imagery and during subsequent field investigation. 1-meter or better lidar data resolution is adequate to resolve small tensile surface cracks, subtle lateral scarps, flow lines and levees, and faint debris fields. These physical details provide critical evidence of landslide movement style and thus inform best practices for reducing slope movement impacts on life, infrastructure, and property.

Due to the geologic and climatic complexity of central and southern Appalachia, slope failure style, and thus post-failure field expression, vary significantly. QL1 lidar-derived imagery permits effective remote sensing of large areas to identify trends in failure style and field expression prior to field verification, allowing more efficient and representative landslide inventory completion when field work begins. Trends in style and physical scale of slope movements are conspicuously distinct within lithotectonic provinces of Appalachia, with the Valley and Ridge, Cumberland and Appalachian Plateaus, and Blue Ridge/western Piedmont all exhibiting characteristic slope movement populations. As the different provinces are fundamentally defined by distinct bedrock structure and rock mechanics, understanding slope failure thresholds and mechanisms within each province requires region- or province-specific expertise. Lidar-supported slope movement study will continue to support sustainable interaction with all parts of the Appalachian landscape and may reveal inter-province connectivity of slope movement populations related to external forcings such as historical storm events, long-term climatic patterns, or seismicity.