New USGS Map Outlines Areas at Biggest Risk of Landslides

A new map from the U.S. Geological Survey (USGS) reveals the areas of the country that are at biggest risk from landslides.

“This new national landslide susceptibility map addresses an important but difficult question: which areas across the entire U.S. are prone to landslides?” Ben Mirus, USGS research geologist, said in a statement. “We are excited that it is now publicly available to help everyone be more prepared — to be a more hazard-ready nation.”

According to the U.S. Landslide Inventory and Susceptibility Map and an accompanying report, about 44% of the U.S. could be vulnerable to landslides, including catastrophic landslide events. 

The landslide inventory map, currently in beta, includes details on where landslides have already occurred, while the new susceptibility map can help in resiliency and land-use planning by showing areas that are more vulnerable to landslides. Previously, the landslide inventory was more disjointed, with different records and data being kept in various formats within varying agencies and departments. The inventory will be continuously updated, and the USGS is accepting additional landslide information to be sent to the email address gs-haz_landslides_inventory@usgs.gov.

As for susceptibility, historically, the focus remained on areas where risks were considered highest, USGS explained. Now, the map offers a more comprehensive look at risks across the U.S., including for Hawaii, Alaska and Puerto Rico.

In using the interactive susceptibility map, users will see increasing risk by color, with white showing little risk, yellow showing increased risk, and darker shades of red showing the highest risk. 

“The updated national landslide susceptibility map could potentially support state and federal agencies in their efforts to determine if landslides are a concern for areas of interest and whether site-specific analyses may be warranted,” USGS noted in its report. “This map may be of particular utility in areas without existing landslide data or only limited local capacity to do additional mapping.”

However, USGS warned that the maps are limited in that they do not provide details into the frequency or magnitude of landslides, which could increase in response to climate change. A 2023 study found that from 2031 to 2060 and 2066 to 2095, landslides caused by extreme precipitation could increase by 7% and 10%, respectively, when compared to landslide averages from 1971 to 2000.

“Although it does not account for frequency or magnitude of landsliding needed to quantify the probability of future landslide impacts, this uniform map provides useful information for stakeholders and partners to inform more detailed hazard or risk assessments. Comparing our map with existing landslide inventories shows areas where landslides were not expected, and thus where more detailed susceptibility assessments may be warranted,” USGS concluded.