## 5 Case Study of Landslide Prone Regions
### United States of America  
As a geologic hazard that may occur anywhere in the United States, landslides are a common occurrence. It has been estimated that they are responsible for 25-50 deaths a year and billions of dollars' worth of economic damage [129]. In the United States, the number of people killed by landslides varies dramatically from year to year. According to more current figures, 93 people died as a result of landslides between 2004 and 2016. Estimates of landslide-related economic losses, however, are fraught with ambiguity in relation to fatality counts. Estimates were made using data from individual homes in southern California that had landslide-related damage that were extrapolated to the whole nation [130, 131]. Similarly, Kentucky's estimated yearly direct repair expenditures for landslide-damaged highways and private homes ranged between $10 million and $20 million US dollars [132]. Indirect losses from decreased economic productivity and other landslide-related expenses, on the other hand, are very difficult to quantify and have not been documented. For the typical range and severity of landslide weather conditions across the United States, upgraded estimates of economic damage are critical, particularly given that the impacts of landslides are anticipated to grow as a result of ongoing climate change, increased disturbances, such as wildfire, and population expansion into landslide-prone terrain [133]. Several landslide-related deaths and catastrophes in the United States have recently heightened public awareness and directed more resources into landslide research and mapping. These shifts in objectives, along with recent technological advancements, have resulted in concentrated attempts to map landslides within specific administrative regions, usually by state or county. Landslide inventories have long served as the basis for research and different kinds of hazard evaluations aimed at minimizing losses. Inventoring the time of slope collapses, for example, is important for improving empirical and deterministic criteria for landslide early warning systems at different scales. Landslide mapping and categorization is usually performed at a local level, or during post-event response operations, with very varied goals and resources provided. Several state geological surveys or agencies in the United States have developed landslide mapping procedures that are well-defined [133]. This has opened the path for thorough landslide inventories inside their different jurisdictional borders. However, because of a lack of guidelines for consistent data collection and administration, landslide data formats may differ significantly across inventories, making it difficult to create a unified national-scale product. Our first steps toward compiling a list of known landslide occurrences in the United States compiled existing, publicly available geodatabases, but reduced them to a uniform subset of attributes that we deemed necessary for developing a comprehensive understanding of landslides and their impacts across the country. The USGS maintains an open repository for seismically induced ground-failure inventory, which includes liquefaction and landslide incidents related to particular earthquakes. The authors of technical reports and scientific journal publications contribute inventories, but the USGS maintains access in a centralized place [134]. Academic researchers in England have created a worldwide database of deadly landslides  
Figure 19: Shallow landslides in Yan’an China, July 2013 [128]. going back to 2004 based on media and other sources. However, state and municipal government organizations in the United States often keep more accurate and complete maps of landslide occurrence, which may contain historical landslides that predate 2007, or may not always include explicit information on the date of occurrence.