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Landslides affect all 50 states and U.S. territories, where they cause 25 to 50 deaths and more than $1 billion in damages each year. Geoscientists study and monitor landslides to identify at-risk areas, prepare populations, and improve our understanding of why, when, and where landslides happen.


2014 Oso, Washington Landslide. Image Credit: USGS/Photo by Mark Reid

Landslides are masses of earth, rock, or debris that move down slopes. Landslides are triggered by one event, but many causes can weaken slopes over time and make them more likely to fail when there is a triggering event. These causes can be both natural and artificial. Landslides often occur in areas with oversteepened slopes, weak soils/bedrock, or de-vegetated slopes (whether by human deforestation or natural events such as wildfires).[1] Some of the most damaging landslides are triggered by water, typically from intense short-term rainfall or long-term saturation of the slope. Both natural and human activities (such as irrigation or seepage) can saturate hillsides. Earthquakes and volcanic eruptions also cause damaging landslides.[1]   Read more

Frequently Asked Questions

Latest News

Cracked road from earthquake
January 30, 2018 On January 30, the Senate Committee on Energy and Natural Resources held a full committee hearing to address the role of the U.S. Geological Survey (USGS), U.S. Forest Service (USFS), and National Oceanic and Atmospheric Administration (NOAA) in preparing for and responding to...
March 22, 2017 Senators Maria Cantwell (D-WA) and Lisa Murkowski (R-AK) introduced the bipartisan National Landslide Preparation Act (S.698) on March 22. The bill directs the U.S. Geological Survey (USGS) to establish a National Landslide Hazards Reduction Program. This program would identify and...
Mount St. Helens
July 12, 2016 The Hazards Caucus Alliance, a network of organizations that promotes nationwide natural disaster resilience, held a briefing to highlight the role that science plays in protecting communities that are vulnerable to lahars. Introductory remarks from Senator Lisa Murkowski (R-AK) were...
Capitol at night
March 17, 2016 Congresswoman Suzan DelBene (D-WA) has introduced new legislation in an effort to decrease losses and damages as a result of landslides.  The new bill, the National Landslide Loss Reduction Act (H.R. 4776) would create the National Landslide Hazards Reduction Program and two...

Case Studies & Factsheets

Cover of AGI Factsheet 2018-003--Using Geologic Maps to Reduce Landslide Risk

Geologic Maps and Landslide Hazards A geologic map is key to understanding landslide risk. The U.S. Geological Survey (USGS) and numerous state geological surveys around the nation prioritize the mapping of landslide-prone areas. Understanding landslide risk is crucial in making decisions around...


More than just volcanic eruptions Volcanic eruptions are a serious hazard. But at many stratovolcanoes in Washington, Oregon, Northern California, and Alaska, landslides and debris flows can be just as dangerous. Some of these - especially volcanic mudflows (lahars) - are directly triggered by...

Fig. 1. A 1995 landslide in Overland Park, Kansas, destroyed two homes and damaged four lots. Credit: Kansas Geological Survey

Defining the Problem Damaging landslides occur even in vertically challenged states like Kansas (Fig. 1). It is important to be able to delineate landslide hazard areas in order to develop appropriate land-use plans. In Leavenworth County, Kansas, geologic maps combined with maps of landslide...

Fig.1. Home in Oakland, CA, destroyed by landslides in 1958. Source: J. Coe, USGS

Defining the Problem The geologic history of the Oakland, California, area has produced steep hillsides and unstable rock and soil that generate damaging landslides during severe storms and wet winters (Fig. 1 and 2). During the 1997-98 rainy-season, the two-county area surrounding Oakland...

Fig. 1. Homeowners and emergency managers are still coping with debris flows and the aftermath of the 2002 Missionary Ridge wildfire near Durango, CO. Credit: P. Winkworth

Defining the Problem Wildfires, such as the Missionary Ridge fire that burned for more than a month in 2002 near Durango, Colorado (Fig. 1), and their aftermath can cause subsequent property and environmental damage. Many areas denuded by the fire are now susceptible to rapid erosion during...

Fig. 3. U.S. Highway 85 crossing the Little Missouri River. Seventy-five percent of the rocks in this photograph, all of those in the foreground and the rocks along the north valley wall in the background have slid and are out of place. Credit: E. Murphy

Defining the Problem U.S Highway 85 and ND Highway 22, along with numerous county roads, buildings, pipelines, and power lines, have been constructed over existing landslides in the Little Missouri Badlands of western North Dakota. Since 1980, the repair and rerouting of damaged sections of...

Research Database Publications

Cover of PP1723; Source: USGS
2006, U.S. Geological Survey (USGS)
In the first half of the 20th century, engineering geology and geotechnical engineering were in their infancy, and dams were often built where landslides provided valley constrictions, often without expert site investigation. Only the most important projects were subjected to careful geologic...
Cover of 90-24; Source: Maine Geological Survey
1990, Maine Geological Survey (MGS)
Identification of landslide prone sites in Maine is imperative in order to maintain the safety of affected developed areas and future developments. Large landslides in Gorham, Maine in 1983 and Rockland, Maine in 1973, a number of smaller landslides, and evidence of historical and prehistorical...
Cover of CAGS_SR_225; Source: California Geological Survey
2012, California Geological Survey (CGS)
On July 12, 2008 remnant moisture from hurricane Bertha moved from the Gulf of Mexico across the southwestern United States bringing tropical moisture to the Eastern Sierra Nevada. Rainfall intensities reportedly as high as 97 mm/hr (3.8 in/hr) occurred for a period of 39 minutes on the Oak Creek...
Fig.1. Home in Oakland, CA, destroyed by landslides in 1958. Source: J. Coe, USGS
2004, American Geosciences Institute (AGI)
In California, detailed modern geologic maps are fundamental for evaluating how susceptible an area is to earthquake-induced landslides.
Cover of SP-30; Source: Colorado Geological Survey
1986, Colorado Geological Survey (CGS)
Study of Ouray–a small mountain city with a long history of destructive debris flows. Includes description of past events, local geology, hydrology, damage incurred, mitigation attempts and costs, and map of hazard zones.
Cover of factsheet; Image credit: Hazards Caucus Alliance
2014, Hazards Caucus Alliance (HCA)
Landslides are a destructive geologic hazard with localized but significant impacts. In an average year in the United States, landslides cause the deaths of 25 to 50 people and economic losses of at least $2 billion. State and local entities take significant responsibility for landslide mitigation...
Cover of fs_landslide_hazards; Source: Washington Division of Geology and Earth Resources
2015, Washington Division of Geology and Earth Resources (WA DGER)
Washington is one of the most landslide-prone states in the country, with hundreds to thousands of events each year. The direct cost of landslide damage includes the repair of roads and property. Indirect costs, such as loss of property value and tax revenue, and environmental effects, such as the...
Cover of 87-4; Source: Maine Geological Survey
1987, Maine Geological Survey (MGS)
Many landslides in Maine have occurred in the marine clay, called the Presumpscot Formation, which covers much of southern Maine. This glacially derived clay was deposited in the sea during the retreat of the late Wisconsinan ice sheet, and subsequently was uplifted by crustal rebound after the...
Cover of PP1617; Source: USGS
2000, U.S. Geological Survey (USGS)
Rapid spilling of 22 acre-feet of water down the steep, 3-mile channel of Ophir Creek killed one, injured four, and destroyed or damaged five houses. Flow evolved into debris flow enroute, and compounded in volume over 30 times.
Cover for USGS FS 2013-3114 ; Source: USGS
2014, U.S. Geological Survey (USGS)
During the second week of September 2013, nearly continuous rainfall caused widespread landslides and flooding in the northern Colorado Front Range. The combination of landslides and flooding was responsible for eight fatalities and caused extensive damage to buildings, highways, and infrastructure...