WP4-Rockfall hazard and risk maps at regional scale




The WP will be developed in two sub-actions:

4.1) Modeling of rockfall on a regional scale.  The first part of the WP is focused on the collection and mapping of thematic layers needed for rockfall simulation (geology, land use, superficial geology, element at risk, existing defensive measures). The next step is the identification and characterization of source areas to produce a map of rockfall source areas in Regione Lombardia and the simulation of different volume scenarios from each source area by using the HY-STONE.

4.2) Hazard study. The second part of the WP is focused on the development of the regional hazard map. The next step will be the intersection of the hazard map with the elements at risk, in order to produce a risk map.





The land use and geomorphological map of Lombardy, available by the Region, has been reclassified into homogeneous land units for the purposes of rockfall modeling with the HY-STONE software. From the union of the two maps a new map was created for the whole of Lombardy, which gathered within it areas of “unique values” with information on both the geomorphological characteristics and land use.

The collapse sources have been defined according to slope criteria and through the use of lithological maps for sub-outcrop and outcropping bodies. The modeling parameters were defined by calibrating events inserted in the WP1 database using the HY-STONE software.

26 landslides were simulated in different lithological and land use contexts. These landslides are partly of the IFFI database and partly of historical events mapped on the ground (eg: Fiumelatte, Cataeggio). For each landslide, the model is calibrated to cover the expansion and distribution of the blocks stopped. The calibrated parameters of each simulation are then analyzed statistically to obtain average values ​​to be applied to the regional model.


The results of rockfall modeling were implemented to create an Hazard map according to the RHV method (Crosta and Agliardi, 2003). The region is than subdivided in 4 hazard classes (1 low hazard, 4 high hazard).


On going research


The hazard map will be the intersec with the elements at risk (buildings, streets, railway line), in order to produce a risk map.