Urban Landslides: Challenges for Forensic Engineering Geologists and Engineers

Abstract

Each year landslides cause 25–50 deaths and on the average $3.5 billion in damage in the United States. Many of these landslides occur in urban settings. Figuring out what caused these urban landslides and also how to prevent them can be a challenge to forensic engineering geologists and geotechnical engineers. Urban landslides are defined as landslides that occur in or near cities, generally involving humans, houses and/or businesses. The importance of studying each slide to determine its cause and then to recommend a mitigation is paramount. Cities need to develop landslide inventory maps and their corresponding susceptibility maps in order to help prevent loss of human life and property from landslides. Control of water and recognition of ancient landslides are two important steps needed in prevention. Case histories involving reactivation of ancient landslides (Kelso, Washington), lack of control of water (Burlingame Place, Bazazz Landslide, Newell Creek Apartments, and Estacada Landslide), and use of LiDAR (Hidden Lakes Landslide) are analyzed to accentuate the above points. The importance of lack of insurance for landslides on normal homeowner policies has great significance.