DEM-resolution control on rainfall-triggered landslide modeling within a triangulated network-based model

Abstract

Catchment slope distribution significantly controls rainfall-triggered landslide modeling, in both direct and indirect ways. Slope directly determines the soil volume associated with instability. Indirectly, it affects the subsurface lateral redistribution of soil moisture across the basin, which in turn determines the water pore pressure conditions that impact slope stability. It is thus clear that the accuracy in reproducing slope distribution may be crucial in slope stability analysis. The resolution of the Digital Elevation Model (DEM) regulates the description of the topography. The correlation between raster resolution and landslide model outputs has been investigated in the literature, both in terms of landslide susceptibility (Arnone et al., 2016) and landslide dynamics (Tran de Viet et al., 2017; Keijsers et al., 2011; Tarolli and Tarboton, 2006). Results demonstrate that the optimal DEM resolution may not necessarily exclude the use of coarser DEMs. This study evaluates the influence of DEM resolution on the slope stability analysis by using a distributed eco-hydrological-landslide model, which implements a Triangulated Irregular Network (TIN) to describe the topography; as well, the model is capable of evaluating vegetation dynamics and predicting shallow landslides triggered by rainfall.