Landslide Hazard Assessment

A hazard is the likelihood that a danger will materialize. A natural hazard is the hazard posed by a potentially damaging natural event or process, such as an earthquake, flood, volcanic eruption, snow avalanche, hurricane, ground subsidence or mass movement. Landslide hazard refers to the potential for the occurrence of a damaging slope failure within a given area and in a given period. To properly define landslide hazard, the magnitude, size, or dimension of the expected failure must also be quantified, deterministically or in probabilistic terms, because the “magnitude” of the event is linked to its destructive power. Landslide hazard is portrayed on maps. A landslide hazard map partitions a territory based upon different levels of landslide hazard (landslide hazard zoning). As it will become clear later, producing a single landslide hazard map is problematic, as different hazard conditions (or probabilities) must be shown on the same map. An ensemble of maps can be prepared to show landslide hazard, and displayed in a GIS. In this chapter, I first examine a definition of landslide hazard, I then introduce a probabilistic model for landslide hazard assessment that fulfils the adopted definition, and I discuss known problems with the given definition and limitations of the proposed probability model. Next, I show three examples of the application of the proposed probability model for different types of landslides and at different scales, from the catchment to the national scale. In the first example, I illustrate an attempt to determine landslide hazard in the Staffora River basin (§ 2.6), exploiting a detailed multi-temporal inventory map and thematic information on geo-environmental factors associated with landslides. In the second example, I describe an attempt to determine levels of landslide hazard in Italy, based on synoptic information on geology, soil types and morphology, and an archive inventory of historical landslide events. In the third example, I exploit a physically-based computer model capable to simulating rock falls for the determination of rock fall hazard in south-eastern Umbria (§ 2.5). ...

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last modified 2018-02-21T16:10:40+01:00