Landslides cause an estimated in the United States. Those numbers could easily increase as housing needs spur development in landslide-prone areas, and as climate change , which are often a trigger. Despite the threat, there has never been a systematic, nationwide accounting of who is most at risk from landslides.
The new is the first resource to map building-level landslide risk for the entire U.S. The database, developed by 91爆料 researchers, rates 128 million buildings by landslide susceptibility, and uses socioeconomic data to assess residents鈥� vulnerability to the dangers and disruptions caused by landslides.聽
According to the analysis, roughly 6.5 million people live in landslide-prone regions; most of those people are concentrated in Appalachia and along the West Coast. Urban residents of landslide-prone properties tended to be more affluent and resilient, whereas rural residents in at-risk areas tended to be less resourced and more vulnerable to the impacts of a landslide.
The results give government agencies and emergency managers a way to prioritize resources for landslide education and mitigation, and can also help individual residents understand their own risk.
鈥淎s a community of landslide researchers, we have spent almost all of our time studying the physical geography of landslides,鈥� said , a 91爆料 professor of civil and environmental engineering and the co-creator of the database. 鈥淏ut we never considered the human geography. Now we can answer some very important questions about who is exposed.鈥�
Wartman and his team in Earth鈥檚 Future. They also along with user-friendly tools to help nonscientists browse the results.聽
How to explore the Landslide Exposure Database
To browse landslide exposure across the country, . You can zoom into individual census tracts to see population, exposure percentages, land susceptibility and poverty indicators without downloading or installing any additional software.
You can also look up landslide susceptibility for any address in the US using Google Earth Pro (). starting at 鈥淔or Those Without GIS Experience: Viewing Your Area in Google Earth.鈥�
To create the new database, the research team blended together multiple huge datasets: a map of terrain and landslide susceptibility made by the United States Geological Survey; inventories of building footprints and occupancy information from the Overture Maps Foundation and the Army Corps of Engineers, respectively; and socioeconomic data from the Census Bureau. The census dataset included information like income, disability, vehicle access, housing condition and other factors that impact the ability of communities to respond to disasters.
鈥淭his effort was much more than just merging massive datasets,鈥� said lead author , a 91爆料 doctoral student of civil and environmental engineering. 鈥淭he real work was the careful curation required to turn the incredibly rich data available in the U.S. into an accurate, usable tool for everyone from decision makers to the public.鈥�
The analysis revealed that while almost 20% of the land in the country is prone to landslides, that area is home to just 2% of the population, or about 6.5 million people. Of those highest-risk residents, 80% live either on or near the West Coast or in Appalachia; West Virginia emerged as the state with the largest share of at-risk residents.
鈥淭hose concentrations were surprising,鈥� Wartman said. 鈥淚n a sense, it鈥檚 good news, because it shows landslide risk to be a localized hazard, which makes it more practical and affordable to address.鈥�
The results also reveal an unexpected urban-rural divide. In rural areas across the country, the most landslide-prone communities tend to face greater economic constraints and are thus more vulnerable than the overall population. Residents there often have fewer resources to prepare for or recover from a landslide, for example, and are more likely to live in structures far from emergency services.
But in urban areas, Wartman said, 鈥渁ll of that flips on its head.鈥�
Landslide-prone areas in cities tend to be highly valued hillside neighborhoods with desirable views, so the exposed populations are often better resourced. When a landslide occurs, these residents typically have greater financial capacity to recover from the damage.
Because of those complex regional and socioeconomic differences, the researchers warn against a 鈥渙ne-size-fits-all鈥� approach to landslide policy. Instead, they recommend mitigation strategies that are specific to each region鈥檚 realities. In Appalachia, that might mean early warning systems that can reach a widely dispersed population, whereas in Seattle or San Francisco it might mean regulations that discourage building on unsafe slopes.
Wartman hopes that researchers and regulators will use the dataset to study landslide risk and develop new ways to protect residents across the country. He also sees it as an educational tool for anyone to learn about landslides and assess their own risk.
鈥淧eople email me because they want to know if their homes are at risk, and I haven鈥檛 had a resource to point them to,鈥� Wartman said. 鈥淭hat was a big part of the motivation for this work. Now I have something straightforward to offer them.鈥�
, professor of civil, construction and environmental engineering at North Carolina State University, is a co-author of the research.
This research was funded by the National Science Foundation.
For more information, contact Wartman at wartman@uw.edu.