Regional methods for shallow landslide hazard evaluation: a comparison between Italy and Central America

Landslides are a serious issue in the Latin American and Caribbean region, causing disasters and casualties every year. Since these regions suffer from endemic poverty and few resources can be allocated for civil protection, the need to maximize results is strong. In order to diminish vulnerability and increase effectiveness of any intervention, a wide knowledge of territory critical situations needs to be achieved. This paper suggests two useful tools to build hazard maps of a chosen territory; these maps can be useful as a Decision Support System (DSS) to help the management of economical resources and to identify the situations that have the greatest need. The two methods proposed are Stability Index MAPping (SINMAP) and the Mora and Vahrson method. Both methods start from the digital terrain model and other various parameters, linked mainly to slope lithology and rainfalls, and obtain a map of the relative hazard from shallow landslides. The methods have been applied to two study cases: one in Guatemala, a perfect example of what has been mentioned about the difficult Central American situation, and one in the Varese district in Italy, a well known site which provides plenty of data and information that was useful to the authors for rigorous testing of methods. Finally the results have been compared, highlighting the strong influence of input data quality on results and the interesting potential of the tested methods; these proved to be successful when input data have enough resolution and to be useful as a DSS in order to identify critical areas and intensify efforts in these areas.