Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 15, 45-57, 2015
https://doi.org/10.5194/nhess-15-45-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
07 Jan 2015
Landslide susceptibility near highways is increased by 1 order of magnitude in the Andes of southern Ecuador, Loja province
A. Brenning2,1, M. Schwinn3, A. P. Ruiz-Páez1,4, and J. Muenchow3 1Department of Geography and Environmental Management, University of Waterloo, Waterloo, Ontario, Canada
2Department of Geography, University of Jena, Löbdergraben 32, 07737 Jena, Germany
3Institute of Geography, University of Erlangen-Nuremberg, Kochstr. 4/4, 91054 Erlangen, Germany
4Instituto de Geografía, Pontificia Universidad Católica de Chile, Santiago, Chile
Abstract. Mountain roads in developing countries are known to increase landslide occurrence due to often inadequate drainage systems and mechanical destabilization of hillslopes by undercutting and overloading. This study empirically investigates landslide initiation frequency along two paved interurban highways in the tropical Andes of southern Ecuador across different climatic regimes. Generalized additive models (GAM) and generalized linear models (GLM) were used to analyze the relationship between mapped landslide initiation points and distance to highway while accounting for topographic, climatic, and geological predictors as possible confounders. A spatial block bootstrap was used to obtain nonparametric confidence intervals for the odds ratio of landslide occurrence near the highways (25 m distance) compared to a 200 m distance. The estimated odds ratio was 18–21, with lower 95% confidence bounds >13 in all analyses. Spatial bootstrap estimation using the GAM supports the higher odds ratio estimate of 21.2 (95% confidence interval: 15.5–25.3). The highway-related effects were observed to fade at about 150 m distance. Road effects appear to be enhanced in geological units characterized by Holocene gravels and Laramide andesite/basalt. Overall, landslide susceptibility was found to be more than 1 order of magnitude higher in close proximity to paved interurban highways in the Andes of southern Ecuador.

Citation: Brenning, A., Schwinn, M., Ruiz-Páez, A. P., and Muenchow, J.: Landslide susceptibility near highways is increased by 1 order of magnitude in the Andes of southern Ecuador, Loja province, Nat. Hazards Earth Syst. Sci., 15, 45-57, https://doi.org/10.5194/nhess-15-45-2015, 2015.
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Short summary
Mountain roads in developing countries often increase landslide occurrence. In this study, landslide initiation frequency along interurban highways was investigated in the Ecuadorian Andes across different climates. Using statistical models, landslides were found to be about 20 times more likely to occur in close proximity to highways compared to areas in 200m distance from highways while accounting for other environmental factors. Road effects appear to be enhanced in some geological units.
Mountain roads in developing countries often increase landslide occurrence. In this study,...
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