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What is a landslide and what causes one?
A landslide is defined as the movement of a mass of rock, debris, or earth down a slope. Landslides are a type of "mass wasting," which denotes any down-slope movement of soil and rock under the direct influence of gravity. The term "landslide" encompasses five modes of slope movement: falls, topples, slides, spreads, and flows. These are further subdivided by the type of geologic material (bedrock, debris, or earth). Debris flows (commonly referred to as mudflows or mudslides) and rock falls are examples of common landslide types.
Almost every landslide has multiple causes. Slope movement occurs when forces acting down-slope (mainly due to gravity) exceed the strength of the earth materials that compose the slope. Causes include factors that increase the effects of down-slope forces and factors that contribute to low or reduced strength. Landslides can be initiated in slopes already on the verge of movement by rainfall, snowmelt, changes in water level, stream erosion, changes in ground water, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors. Earthquake shaking and other factors can also induce landslides underwater. These landslides are called submarine landslides. Submarine landslides sometimes cause tsunamis that damage coastal areas.
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The 3D Elevation Program—Landslide recognition, hazard assessment, and mitigation support
The U.S. Geological Survey (USGS) Landslide Hazards Program conducts landslide hazard assessments, pursues landslide investigations and forecasts, provides technical assistance to respond to landslide emergencies, and engages in outreach. All of these activities benefit from the availability of high-resolution, three-dimensional (3D) elevation...
Lukas, Vicki; Carswell, Jr., William J.
Real-time monitoring of landslides
Landslides cause fatalities and property damage throughout the Nation. To reduce the impact from hazardous landslides, the U.S. Geological Survey develops and uses real-time and near-real-time landslide monitoring systems. Monitoring can detect when hillslopes are primed for sliding and can provide early indications of rapid, catastrophic movement...
Reid, Mark E.; LaHusen, Richard G.; Baum, Rex L.; Kean, Jason W.; Schulz, William H.; Highland, Lynn M.
The Landslide Handbook - A Guide to Understanding Landslides
This handbook is intended to be a resource for people affected by landslides to acquire further knowledge, especially about the conditions that are unique to their neighborhoods and communities. Considerable literature and research are available concerning landslides, but unfortunately little of it is synthesized and integrated to address the...
Highland, Lynn M.; Bobrowsky, Peter
Video documentation of experiments at the USGS debris-flow flume 1992–2017
This set of videos presents about 18 hours of footage documenting the 163 experiments conducted at the USGS debris-flow flume from 1992 to 2017. Owing to improvements in video technology over the years, the quality of footage from recent experiments generally exceeds that from earlier experiments.Use the list below to access the individual videos...
Logan, Matthew; Iverson, Richard M.
Landslide Hazards - A National Threat
Landslides occur and can cause damage in all 50 States. Severe storms, earthquakes, volcanic activity, coastal wave attack, and wildfires can cause widespread slope instability. Landslide danger may be high even as emergency personnel are providing rescue and recovery services. To address landslide hazards, several questions must be considered...
Southern California landslides-an overview
Southern California lies astride a major tectonic plate boundary defined by the San Andreas Fault and numerous related faults that are spread across a broad region. This dynamic tectonic environment has created a spectacular landscape of rugged mountains and steep-walled valleys that compose much of the region’s scenic beauty. Unfortunately...
Landslide types and processes
Highland, Lynn
Debris-Flow Hazards in the United States
Highland, Lynn; Ellen, Stephenson D.; Christian, Sarah B.; Brown, William M.
Landslide Assistance from the Air
The USGS uses cutting edge technologies to investigate and forecast landslides and other natural hazards.
Huge landslide on California’s Big Sur coast continues to change
The Mud Creek landslide on California’s Big Sur coast keeps eroding.
USGS maps, measures huge landslide on California's Big Sur coast
USGS scientists analyzing before-and-after air photos have calculated the size of the May 20 landslide on California’s Big Sur coast, about 140 miles south of San Francisco.
EarthView–Landslide Spreads 6 Miles Across Glacier Bay National Park
Two snapshots from Landsat show the extent of a landslide in an Alaska National Park.
El Nino May Trigger Landslides... USGS Map Indicates Susceptibility and Incidence of Landslides
Floods, coastal erosion and heavy precipitation aren’t the only predicted consequences of the El Nino phenomena. Landslides and debris flows could happen in areas where intense rainfall occurs.
Big Sur Landslide fly around
Big Sur Landslide fly around from May 27, 2017, a preliminary computer animation. The slide created roughly 13 acres of new California land.
Big Sur landslide on May 20, 2017
USGS air photo of the Mud Creek landslide, taken on May 27, 2017.
2014 Landslide in Washington State
Photograph from aerial survey showing the upper parts of the 2014 landslide in northwest Washington. Photograph credit: Jonathan Godt, USGS
New Zealand Landslides
Photograph showing landslides covering State Route 1 near Ohau Point. The route was impacted my several landslides and is the main north-south highway on the eastern part of the South Island of New Zealand.
As many as 80,000 landslides occurred as the result of a magnitude 7.8 earthquake in New Zealand in November of 2016. The earthquake and landslides caused
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2005 Landslide in Conchita, CA
This landslide occurred at La Conchita, California in 2005. Ten people were killed.
Volcano Web Shorts 2: Debris Flows
Debris flows are hazardous flows of rock, sediment and water that surge down mountain slopes and into adjacent valleys. Hydrologist Richard Iverson describes the nature of debris-flow research and explains how debris flow experiments are conducted at the USGS Debris Flow Flume, west of Eugene, Oregon. Spectacular debris flow footage, recorded by Franck Lavigne of the
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Laser scanning the entire Cleveland Corral landslide
Laser scanning the entire Cleveland Corral landslide from across the valley during an active spring (2010). Repeat scans are used to detect movement throughout the slide.
landslide graphic
graphic illustration of the parts of a landslide
Mill Creek landslide
Photo 1: Aerial view of the Mill Creek landslide blocking Highway 50.