Toward and assessment of climate change impact of landslide occurrence in Central Italy through physically-based approaches

Landslides are one of the most dangerous and widespread natural hazards that cause every year loss of human lifeand damage to properties. Nowadays, many approaches and models with the purpose to assess landslide hazardare available. Besides the evaluation of the occurrence of landslide over an area, these models can be used withbenefits to assess the effect of climate change on this kind of natural hazard, in order to mitigate the impact.In this study, the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability model (TRIGRS) hasbeen used to assess the variation in landslide occurrence in Central Italy. The rainfall projections of 6 RegionalCirculation Models (RCMs) were downscaled and weather generators were used for obtaining hourly rainfalltime series from daily RCMs raw data. Then, TRIGRS was employed to evaluate the stability conditions overthe analysis area during three different periods (1988-2005 as baseline, 2040-2069 and 2070-2069). For eachrainfall projection and for each temporal horizon, a rainfall event characterized by a return period of 5, 10, and50 years of daily rainfall is built and used to drive the model. The variation in the number of unstable grid cellsbetween present and future periods is considered to assess the impact of climate change on landslide occurrence.Preliminary results showed that the effects induced by the expected climatic trends are well reproduced by thephysically-based model, providing a worsening of the stability conditions when more severe climatic conditionsare considered to drive the model.