Deforestation controls landslide susceptibility in Far-Western Nepal

Abstract

Landslides are a major problem in the Far-Western region of Nepal, where one of the highest densities of shallow landslides within the country is observed. However, there is still a lack of understanding around the relative impact of deforestation as a predisposing factor. Here, we use remote-sensing techniques and freely accessible satellite data to quantify the effects of deforestation and related agriculture practices in the assessment of landslide susceptibility. We use a new regional landslide inventory of 8,778 events dated between 1993 to 2018 to train and validate bivariate landslide susceptibility models, in which preceding land cover/land use is included as a predisposition factor. Our results show that the use of land-cover /land-use maps enhances the average probability of model success by 7.9%. Besides, we assess land-cover changes for a period of 1 to 10 years prior to each landslide event to analyze the relative incidence of changes related to deforestation and agricultural uses. The analysis suggests that agricultural practices and deforestation that occur 5–7 years preceding the landslide event have a significant influence on the landslide occurrence (+16%). Our results reveal that negligent anthropological land use practices can significantly enhance landslide risk.