Change Detection for a Slow-Moving Soil Landslide Using Multi-Source LiDAR

ABSTRACT Many slopes continue to exhibit slow movement even after mitigation, and these subtle deformations are often difficult to detect. Internal deformation at depth may produce minor surface expression, yet small topographic changes can influence roadway performance and gradually evolve into serious instability. These issues are critical along high-traffic transportation corridors, where slope failure poses elevated risks. This study evaluated the ability of high-resolution repeated light detection and ranging (LiDAR) monitoring to detect subtle slope movement and quantify surface changes such as erosion, deposition, and displacement and verified results through field observations and inclinometer data. Uncrewed aerial system–based LiDAR was used to monitor a 0.24 km2 (59 acre) landslide located near an interstate highway in eastern Tennessee. Borehole inclinometers indicated ongoing movements up to 1.2 cm (0.47 in.) per year along multiple failure surfaces at varying depths. High-resolution LiDAR data collected in winter 2024 produced a 5 cm (1.97 in.) digital elevation model, which was compared to 0.76 m (2.5 ft) aerial LiDAR from 2015. The analysis revealed scarp and toe positions shifting 30–106 cm (11.8–41.7 in.) per year and elevation changes ranging from 2.3 m (−7.4 ft) erosion to 2.0 m (+6.6 ft) deposition. Although widespread geomorphic change was limited, persistent surface deformation indicated ongoing landslide activity and future risk to the adjacent roadway. Field verification and inclinometer comparisons confirmed the LiDAR-based assessments, demonstrating the value of repeated LiDAR monitoring for evaluating the surface expression of slow-moving landslides and supporting long-term transportation infrastructure management.