Automatic delineation of geomorphological slope-units and their optimization for landslide susceptibility modelling

Abstract

Abstract. Automatic subdivision of landscapes into terrain units remains a challenge. Slope-units are terrain units bounded by drainage and divide lines, but their use in hydrological and geomorphological studies is limited because of the lack of reliable software for their automatic delineation. We present the r.slopeunits software for the automatic delineation of slope-units, given a digital elevation model and a few input parameters. We further propose an approach for the selection of optimal parameters controlling the terrain subdivision for landslide susceptibility modelling. We tested the software and the optimization approach in Central Italy, where terrain, landslide, and geo-environmental information was available. The software was capable of capturing the variability of the landscape, and to partition the study area into slope-units suited for landslide susceptibility modelling and zonation. We expect r.slopeunits to be used in different physiographical settings for the production of reliable and reproducible landslide susceptibility zonations.