Disaggregation of landslide risk

This study introduces a new framework that estimates building-level landslide risk across entire cities and regions, expressing risk in terms that people can easily understand and compare: financial losses and threats to life. Landslides are a damaging and deadly hazard globally. However, current approaches to managing landslides rely primarily on susceptibility maps that show where landslides might occur, without quantifying how often failures happen and how far debris might travel (i.e., landslide hazard), or what damage could result (i.e., landslide risk). This makes it difficult for communities to decide where development is safe. 

Applying their model to the landslide-prone city of Seattle, Washington, USA, the authors find that landslides triggered by frequent rain cause more damage over time than those from catastrophic but infrequent earthquakes. Risk varies dramatically over short distances—even between adjacent properties—and, counterintuitively, where landslides most frequently occur is not necessarily where they cause the most harm. Different landslide types and triggers pose unique threats to humans versus structures, enabling tailored risk reduction strategies. This framework represents a critical step toward making landslide risk assessment practical and accessible for cities and regions worldwide that face increasing landslide threats from climate change and urban expansion.