Application of a process-based shallow landslide hazard model over a broad area in Central Italy

Landslides
By: , and 

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Abstract

Process-based models are widely used for rainfall-induced shallow landslide forecasting. Previous studies have successfully applied the U.S. Geological Survey’s Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability (TRIGRS) model (Baum et al. 2002) to compute infiltration-driven changes in the hillslopes’ factor of safety on small scales (i.e., tens of square kilometers). Soil data input for such models are difficult to obtain across larger regions. This work describes a novel methodology for the application of TRIGRS over broad areas with relatively uniform hydrogeological properties. The study area is a 550-km2 region in Central Italy covered by post-orogenic Quaternary sediments. Due to the lack of field data, we assigned mechanical and hydrological property values through a statistical analysis based on literature review of soils matching the local lithologies. We calibrated the model using rainfall data from 25 historical rainfall events that triggered landslides. We compared the variation of pressure head and factor of safety with the landslide occurrence to identify the best fitting input conditions. Using calibrated inputs and a soil depth model, we ran TRIGRS for the study area. Receiver operating characteristic (ROC) analysis, comparing the model’s output with a shallow landslide inventory, shows that TRIGRS effectively simulated the instability conditions in the post-orogenic complex during historical rainfall scenarios. The implication of this work is that rainfall-induced landslides over large regions may be predicted by a deterministic model, even where data on geotechnical and hydraulic properties as well as temporal changes in topography or subsurface conditions are not available.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Application of a process-based shallow landslide hazard model over a broad area in Central Italy
Series title Landslides
DOI 10.1007/s10346-015-0670-6
Year Published 2015
Language English
Publisher Springer-Verlag
Publisher location Berlin, Germany
Contributing office(s) Geologic Hazards Science Center
Description 18 p.
First page 1
Last page 18
Country Italy
Other Geospatial Esino river basin, Marche region
Online Only (Y/N) N
Additional Online Files (Y/N) N