Landslide Occurrence Analysis in a Data-Scarce Region: The Northern Andes of Ecuador

Landslide susceptibility assessment in data-scarce environments remains challenging. In the northern Andes of Ecuador, the interaction of hypothesized triggers with confounding predisposing factors of landslide occurrences is limited. We investigate the relationship between landslide records and geological, topographic, land use, vegetation and climatic factors in the province of Imbabura using generalized linear models (GLM) and generalized additive models (GAM). Both models are instrumental in identifying that a rainfall increase of one standard deviation in monthly precipitation raises the odds of landslide occurrence, with estimates of 8.84 and 15.84, respectively. The GAM slightly outperformed the GLM by capturing modest non-linear effects, particularly for elevation and profile curvature. Elevation and slope aspect show non-linear and linear tendencies, respectively, although their effects were marginal rather than significant at the 5% level in the selected GAM. Landslides were more likely under wetter conditions at intermediate elevations and on northwestern-facing slopes where ground moisture gradients condition slope stability. Furthermore, the combined effect of agricultural and livestock land uses did not show influence, calling for attention on effects that the scale of analysis did not address. The results provide a baseline framework for rainfall-related landslide occurrence assessment in developing regions with limited data availability.