Disaggregation of Landslide Risk

Abstract Quantifying and disaggregating landslide risk through probabilistic landslide risk analysis (PLRA) is critical for land use regulation and risk reduction. However, no transferable model for PLRA currently exists that resolves landslide consequences to individual buildings at regional scales. We introduce the physically‐based MM 3 model for multimodal landslide risk analysis and apply it to Seattle, Washington, USA. Frequent precipitation‐induced shallow landslides govern landslide risk in Seattle, although ground shaking from infrequent earthquakes, such as those anticipated on the Seattle Fault and Cascadia Subduction Zone, could expose over 60,000 people and 12,000 buildings to landslides. Critically, building‐specific risk profiles vary by orders‐of‐magnitude even at neighboring properties, with different landslide modes and triggers posing distinct threats to human life versus structural integrity—enabling highly tailored mitigation strategies. Significantly more buildings face landslide risk than are currently designated as landslide‐prone under susceptibility‐based policies, primarily due to runout being excluded in susceptibility mapping. By quantifying and disaggregating landslide risk at building resolution across regional scales, MM 3 provides a foundation for translating landslide science into actionable, risk‐informed land use policy.