What was the biggest landslide in the world?

The largest landslide on Earth in recorded history occurred during the 1980 eruption of Mount St. Helens, a volcano in the Cascade Mountain Range in the State of Washington, USA. The volume of material was 0.67 cubic miles (2.8 cubic kilometers) and the landslide traveled about 14 miles down the North Fork Toutle River. Average landslide depth was 150 feet (maximum depth 600 feet). The landslide velocity was 70-150 miles per hour.

Learn more: Worldwide Catastrophic Landslides of the 20th Century

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What should I know about wildfires and debris flows?

Wildland fires are inevitable in the western United States. Expansion of human development into forested areas has created a situation where wildfires can adversely affect lives and property, as can the flooding and landslides that occur in the aftermath of the fires. There is a need to develop tools and methods to identify and quantify the...

How do landslides cause tsunamis?

Tsunamis are large, potentially deadly and destructive sea waves, most of which are formed as a result of submarine earthquakes. They can also result from the eruption or collapse of island or coastal volcanoes and from giant landslides on marine margins. These landslides, in turn, are often triggered by earthquakes. Tsunamis can be generated on...

Under what circumstances do U.S. Geological Survey landslide personnel conduct field work in landslide-prone areas?

USGS landslide researchers have ongoing field projects in several areas of the United States, including parts of the Pacific coastal ranges, Rocky Mountains, and the Appalachians. USGS scientists also respond to major landslide events, including some that result in federally-declared disasters. In some cases, USGS scientists respond to landslides...

Can major landslides and debris flows happen in all areas of the U.S.?

Landslides can and do occur in every state and territory of the U.S.; however, the type, severity and frequency of landslide activity varies from place to place, depending on the terrain, geology, and climate. Major storms have caused major or widespread landslides in Washington state, Oregon, California, Colorado, Idaho, Hawaii, Virginia, Ohio,...

Is there a list of the largest landslides in the world?

See the list of Catastrophic Landslides of the 20th Century - Worldwide . The five largest Worldwide Landslides are: 1911 - Tadzhik Republic - 2,000,000,000 cubic meters of material - 54 killed 1919 - Indonesia - 185 square kilometers of material - 5,110 killed 1920 - China - unknown volume - 100,000 killed 1921 - Kazakh Republic - unknown volume...

What is the difference between a landslide advisory, a landslide watch, and a landslide warning?

An advisory is a general statement about the potential of landslide activity in a given region relative to developing rainfall predictions. An advisory may include general statements about rainfall conditions that can lead to debris-flow activity, and list precautions to be taken in the event of heavy rainfall. A watch means that landslide-...

How many deaths result from landslides each year?

An average of 25-50 people are killed by landslides each year in the United States. The worldwide death toll per year due to landslides is in the thousands. Most landslide fatalities are from rock falls, debris-flows, or volcanic debris flows (called lahars). Twenty three people were killed, at least 167 injured, and more than 400 homes were...

Do human activities cause landslides?

Yes, in some cases human activities can be a contributing factor in causing landslides. Many human-caused landslides can be avoided or mitigated. They are commonly a result of building roads and structures without adequate grading of slopes, poorly planned alteration of drainage patterns, and disturbing old landslides. Detailed on-site...

Why study landslides?

Landslides are a serious geologic hazard common to almost every State in the United States. As people move into new areas of hilly or mountainous terrain, it is important to understand the nature of their potential exposure to landslide hazards, and how cities, towns, and counties can plan for land-use, engineering of new construction and...

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...
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Date published: July 20, 2017

Landslide Assistance from the Air

The USGS uses cutting edge technologies to investigate and forecast landslides and other natural hazards.

Date published: June 1, 2017

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. 

Date published: July 28, 2015

Landslides Triggered by Nepal Earthquakes

MENLO PARK, Calif. — A new report from the U.S. Geological Survey provides critical landslide-hazard expertise to Nepalese agencies and villages affected by the April 25, magnitude 7.8 earthquake that shook much of central Nepal.

Date published: May 18, 2011

New Time-lapse Animation of Mount St. Helens 1980 Ash Cloud as Seen from Space

Scientists at the U.S. Geological Survey’s Cascades Volcano Observatory rediscovered an old cache of satellite images captured on May 18-19, 1980, and linked them together to create a time-lapse movie of Mount St. Helens' eruptive ash cloud movement across the western United States.

Date published: October 13, 2005

Protecting Communities from Landslides

New report identifies best practices for protecting communities
 

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A USGS Research Geologist takes photographs of Puerto Rican hillsides from a U.S. Army helicopter to document landslides.
December 31, 2017

Documenting landslides in Puerto Rico caused by Hurricane Maria.

Bill Schulz, USGS Research Geologist, takes photographs of Puerto Rican hillsides from a U.S. Army helicopter to document landslides caused by Hurricane Maria. This work will help identify areas around Puerto Rico with the highest risk of more landslides, which is information the Federal Emergency Management Agency will use to determine the best way to mitigate and prepare

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Big Sur landslide on May 20, 2017 showing material across Highway 1.
May 27, 2017

Big Sur landslide on May 20, 2017

USGS air photo of the Mud Creek landslide, taken on May 27, 2017.

Oso landslide. Huge swath of mountain missing.
December 31, 2014

Oso landslide

Oso landslide 2014

Attribution: Natural Hazards
Digital Elevation Map of Mount St. Helens pre and post 1980
September 21, 2012

Digital Elevation Map of Mount St. Helens pre and post 1980

The shaded relief image was produced from LIDAR data. LIDAR is an acronym for Light Detection and Ranging, a modern remote sensing technique used to map topography very accurately—more so than is possible with older techniques. The crater is 1.2 miles (1.9km) wide east-west. Elsewhere the scale varies owing to the oblique viewing angle. The landslide deposit includes the

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May 9, 2012

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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Attribution: Volcano Hazards
Photo of the Mud Creed landslide near Big Sur, California
July 31, 2011

Mud Creek landslide near Big Sur

A view of the Mud Creek landslide near Big Sur, California, from the research vessel Snavely

Attribution: Natural Hazards
Image: 2005 Landslide in La Conchita, CA
January 10, 2005

2005 Landslide in La Conchita, CA

On January 10, 2005, a landslide struck the community of La Conchita in Ventura County, California, destroying or seriously damaging 36 houses and killing 10 people. For a USGS rerpot on this event, please see USGS Open-file report, "Landslide Hazards at La Conchita, California."

Attribution: Natural Hazards
North Flank of Mount St. Helens
April 12, 2004

North Flank of Mount St. Helens

This view from near the Forest Learning Center along Highway 504 shows the north flank of Mount St. Helens, from which much of the debris from the massive 1980 avalanche/eruption spilled into the Toutle River valley. The eruption produced about 3 cubic kilometers of ash and sediment that was distributed across the landscape around the volcano. This material is being

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Image shows a map with potential volcano hazards to the surrounding area for Mount St. Helens
November 30, 2000

Mount St. Helens Simplified Volcano Hazards Map

Mount St. Helens, Washington simplified hazards map showing potential impact area for ground-based hazards during a volcanic event. More simplified volcano hazard maps for the other Cascades Volcanoes can be found here.

Volcano erupting and spewing a huge cloud of rock and ash into the sky.
May 18, 1980

Mount Saint Helens eruption

On Sunday, May 18, 1980 at 8:32 a.m., the bulging north flank of Mount St. Helens slid away in a massive landslide -- the largest in recorded history. Seconds later, the uncorked volcano exploded and blasted rocks northward across forest ridges and valleys, destroying everything in its path within minutes.

Image: 2008 Landslide Near Hongyan Resort, China

2008 Landslide Near Hongyan Resort, China

The May 12, 2008, Great Sichuan Earthquake, also called the Wenchuan Earthquake, occurred at 14:28 local time, in Sichuan Province, China. The earthquake magnitudes were Mw = 7.9 (USGS), Ms = 8.0 (Chinese Earthquake Administration). The epicenter was 80 km west-northwest of Chengdu, the capital city of Sichuan province. Damage by earthquake-induced landslides was

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Attribution: Natural Hazards