Climate change impact for spatial landslide susceptibility

Climate change is influencing future precipitation patterns. Especially the short intense rainfalls are expected to increase. Intense precipitation is regarded as one of the main landslide triggering factors. In order to investigate the likely impacts of precipitation change on spatial and temporal patterns of landslide susceptibility it is important to distinguish which type of rainfall has a major influence. Therefore, this study analyses the influence of precipitation maxima and antecedent rainfall conditions on landslide susceptibility. Other dynamic factors such as land cover change are excluded from the analysis. Logistic regression was applied to derive landslide susceptibility maps based on different climate change scenarios. Independent variables were several precipitation indices, current land cover maps and DTM derivatives (e.g. the slope gradient, aspect and curvature). The dependent variable was an inventory of shallow landslides for the period 1962–2007. The extrapolation of landslide susceptibility to the future was performed by applying the coefficients determined from past precipitation indices to those computed from future climate scenarios. The assumption herein is that conditions of the future that are similar to the past result in the same consequences. The study area Waidhofen/Ybbs is located in the alpine foreland in the province of Lower Austria. The predominant lithology is composed of calcareous rocks and Flysch. The land cover is mainly grassland and forest. The results show distinct changes in landslide susceptibility for some regions of the study area. Altered precipitation patterns intensify landslide susceptibility as well as enlarge susceptible areas.