ASSESSING LANDSLIDE DYNAMICS: THE EFFICACY OF STREAMLINED LANDSLIDE IDENTIFICATION PROTOCOL (SLIP) AND DENSITY ANALYSIS IN GREER’S FERRY LAKE, ARKANSAS

This study assesses the effectiveness of the Streamlined Landslide Identification Protocol (SLIP) in generating landslide inventories and conducting density analyses in regions characterized by slope instability and various forms of mass wasting. Greer’s Ferry Lake, Arkansas, is the focal area for this investigation. The objectives are to (1) demonstrate SLIP's effectiveness in generating landslide inventories for density analysis, (2) determine whether the frequency of landslides is contingent upon their size, with smaller landslides occurring more frequently than larger ones, and (3) investigate whether land use and land cover influence landslide initiation, with areas near human-influenced infrastructure expected to exhibit the highest landslide density. SLIP involves constructing a landslide database by categorizing observable features (head scarp, internal scarp, flanks, internal features, and toe) into confidence intervals (CI = 10, 20, 30, and 40) using a 1-m LiDAR digital elevation model (DEM). A CI of 40 indicates a high likelihood of recent (historic) landslide occurrences, while a CI of 10 or 20 suggests a low likelihood (prehistoric occurrence) of landslides. The completed SLIP landslide inventory identifies 2,610 landslides, with 628 having a high confidence interval of 30 or 40. Analysis of the inventory reveals a total landslide density of approximately 5.89 slope failures per square mile (2.27 / Km²), with high confidence landslides having a density of approximately 1.42 slope failures per square mile (0.55 / Km²). Scatterplot analysis indicates a positive relationship between landslide area and frequency for both total landslides (R² = 0.9795) and high confidence landslides (R² = 0.9742), highlighting an increase in landslide frequency with smaller sizes. Contrary to initial expectations, only 4.94% of landslides were found within areas surrounding infrastructure, while the majority occurred in forested/vegetated regions (18.7% coverage) in Greer’s Ferry Lake, AR. In conclusion, the results demonstrate that SLIP, when coupled with a high-resolution DEM, is effective for creating comprehensive landslide inventories and conducting density analyses.