Analysis of Inventories

The information shown on landslide inventories can be used for a variety of analyses, including: (i) investigating landslide spatial abundance, through the production of landslide density maps; (ii) comparing inventory maps obtained from different sources (e.g., archive and geomorphological) for the same area; (iii) evaluating the completeness of the inventories; (iv) ascertaining landslide geographical persistence, by comparing event and geomorphological inventories; (v) estimating the frequency of slope failure occurrence, by analysing historical catalogues of landslide events or multi-temporal inventory maps; (vi) obtaining the statistics of landslide size; (vii) ascertaining landslide susceptibility and hazards, including the validation of the obtained susceptibility and hazard forecasts; (viii) determining the possible impact of landslides on built-up areas or the infrastructure; and (ix) contributing to establish levels of landslide risk. The quality and reliability of the different analyses obtained from a landslide inventory depend largely (often entirely) on the quality and completeness of the original landslide map. For this reason, one should always: (i) aim at compiling accurate and precise inventories, (ii) document the sources of information used to obtain the inventories, (iii) accurately describe the techniques, methods and tools used to prepare or compile the inventories, and (iv) try to assess the completeness of the obtained inventories. Limitations of landslide inventories should always be known (i.e., explicit and clear) to the users of the maps or the archives. In this chapter, I discuss some of the possible applications of landslide inventories. I first demonstrate the construction and use of landslide density maps. I then show methods to compare geomorphological and historical inventories. I discuss an index to quantify the degree of matching between inventories, and I show an application for the comparison of the three landslide maps available for the Collazzone study area. I further discuss the issue of the completeness of the landslide inventories, and I use two event inventories available for Umbria to investigate geographical landslide persistence. Finally, I show how to ascertain the temporal frequency of slope failures from archive inventories. ...