Shallow landslide susceptibility map at a regional scale (Asturias, NW Spain). A heuristic-driven approach

Abstract

The study area (Asturias), located in NW Spain, is a mountainous region extending over 10,000 km2, where shallow landslides triggered after heavy rainfall episodes are very frequent and pose a major threat and hazard to infrastructure and human populations, causing significant economic losses and damage every year. In this regard, Shallow Landslide Susceptibility Mapping (SLSM) represents a very powerful tool for managers and agencies dealing with landslide hazards and land planning. Here we produced an SLSM for Asturias based on basic geological/geomorphological maps and a heuristic approach. The regional-scale model built here has a cell resolution of 50 m and combines bedrock geology, and surface deposits mapped at a1:25k scale together with a digital slope model. The resulting map was compared with two local inventories of landslides, giving a goodness of fit of 80 and 77.5%. To better understand the results, the erroneous data have been reviewed individually and the causes of error were analysed. Our study highlights the value of high-quality geological and, especially, geomorphological mapping for landslide susceptibility assessments

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