Skip to Main Content


The Val Pola rock avalanche began when a sagging slope failed due to toe unloading. The mass then plunged down into a narrow valley from a considerable height, crossed the valley, parted, rebounded, and, in part, ran back up to the source slope. Seven men were killed in this stage. The destabilization of this 34 × 106 m3 rock mass (mostly diorite) was triggered by heavy rainfalls that caused shallow landslides on the Val Pola sides and debris flows along the Val Pola thalweg. These processes resulted in a 35 m deepening of the canyon along the toe of the sagging slope. The morphology of the accumulation is mostly characterized by frequent, aligned hummocks and depressions, by reverse runup ridges, and by a narrow, 900-m-long, tongue-like downstream extension. The interaction between the moving mass and local morphology resulted in a relatively moderate runout and an unusually high degree of spreading. The north arm of the rock avalanche displaced the water of a preexisting landslide-dammed lake, generating a wave that killed 22 people more than 2 km upstream. A new and greater lake was formed as a consequence of the event. The systematic identification of sagging slopes and the establishment of reference geotechnical models are suggested for hazard prevention and emergency management.

You do not currently have access to this chapter.

Figures & Tables




Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal