What is a landslide hazard map?

Several kinds of maps are used to depict danger from landslides. These maps might be as simple as a map that uses the locations of old landslides to indicate potential instability, or as complex as a map incorporating probabilities based on variables such as rainfall, slope angle, soil type, and levels of earthquake shaking. The following types of maps are used to describe and depict landslide hazards:

Landslide inventory maps show landslide locations and might show the dimensions and geographical extent of each landslide. One clue to the location of future landsliding is the distribution of past movement, so maps that show the location and size of landslides are helpful in predicting the hazard for an area.  

Examples of landslide inventory maps:

Landslide susceptibility maps describe the relative likelihood of future landsliding based solely on the intrinsic properties of a locale or site. Some organizations use the term “landslide potential map” for maps of this kind. Prior failure (from a landslide inventory), rock or soil strength, and steepness of slope are three of the more important site factors that determine susceptibility.

Examples of landslide susceptibility maps:

Landslide hazard maps indicate the possibility of landslides occurring throughout a given area. An ideal landslide hazard map shows not only the chances that a landslide may form at a particular place, but also the chance that it may travel downslope a given distance.

Examples of landslide hazard maps:

Examples of potential landslide maps:

Landslide risk maps show landslide potential along with the expected losses to life and property, should a landslide occur. Risk maps combine the probability information from a landslide hazard map with an analysis of all possible consequences (property damage, casualties, and loss of service).

Related Content

Filter Total Items: 7

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...

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 worldwide catastrophic landslides of the 20th century . 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 was the biggest landslide in the world?

The world's biggest historic landslide 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 2.8 cubic kilometers (km). The world's biggest prehistoric landslide (discovered so far and on land), is in southwestern Iran, and is named the Saidmarreh...

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). At least 20 people were killed by a series of mudslides in California's Santa Barbara...

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...
Filter Total Items: 5
Date published: January 26, 2018

USGS Geologists Join Efforts in Montecito to Assess Debris-Flow Aftermath

Days after fatal debris flows devastated Southern California’s Montecito community,  a team of U.S. Geological Survey geologists joined county, state, and federal partners to survey and  evaluate the aftermath.

 

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: July 11, 2017

Huge landslide on California’s Big Sur coast continues to change

The Mud Creek landslide on California’s Big Sur coast keeps eroding.

Date published: May 27, 2017

USGS helping to monitor and assess huge Big Sur landslide

USGS is collecting and analyzing air photos to help monitor a huge landslide that occurred May 20 on California’s Big Sur coast.

Date published: June 25, 1999

Landslides Will Continue to Impact U.S. - Tumbling Rocks Cost Dollars and Lives

Scenic rock cliffs falling to valley floors, rocks ripping out mountainsides, mud and debris moving down valleys at deadly speeds, mines and caves collapsing, and ocean and river bluffs sliding into the water -- all describe one of the nation’s most underestimated hazards -- landslides.

Filter Total Items: 9
Aerial photograph looking from an airplane down on the Big Sur Landslide in California.
July 7, 2017

Big Sur Landslide, July 7, 2017

USGS scientists continue to monitor the slide by collecting imagery every couple of weeks, weather permitting. Pilot Bob Van Wagenen, contracted through the Department of the Interior’s Office of Aviation Services, takes air photos for Jon Warrick’s Big Sur Landslide team, flying out of the Watsonville Municipal Airport in a Cessna 182R. He uses a camera-plus-GPS system

...
October 27, 2016

PubTalk 10/2016 — Rockfalls in California's Sierra Nevada

Rock falls in California’s Sierra Nevada - Pursuing explanations for exfoliation and seemingly spontaneous fracture of rock
 

Landsat image showing the landslide in Glacier Bay
August 7, 2016

Landslide Spreads 6 Miles Across Glacier Bay National Park

On June 28, 2016, a 4,000-foot-high mountainside in Glacier Bay National Park and Preserve collapsed, sending rocky debris equivalent to 60 million mid-size SUVs tumbling onto nearby Lamplugh Glacier.  Almost 6 weeks later, on August 7, the Operational Land Imager sensor aboard Landsat 8 captured the black stain of the landslide in the image on the right. No such

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

Oso landslide

Oso landslide 2014

Attribution: Natural Hazards
Image: 2014 Landslide in Washington State
March 24, 2014

2014 Landslide in Washington State

Photograph from an aerial survey showing the extent and impacts from the landslide in northwest Washington that occurred on March 22, 2014. The survey was conducted by the Washington State Department of Transportation, Washington State Department of Natural Resources, USGS, and King County Sheriff's Office.

Attribution: Natural Hazards
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

...
Downstream impacts of a post-fire debris-flow in Mullally Canyon
February 6, 2010

LS Post Fire Debris Flow

Downstream impacts of a post-fire debris-flow in Mullally Canyon on February 6, 2010, near La Canada-Flintridge, California. Debris flow was generated during a burst of high-intensity rainfall over the area burned by the September 2009 Station Fire. 

Landslide monitoring station with the San Gabriel mountains in the background, post wildfire with no vegetation
December 31, 2009

Landslide monitoring site

Original rainfall and telemetry station established after the 2009 Station Fire, CA.

The aftermath of the January 9, 2018 debris flows in Montecito, California.

Debris flows in Montecito, California

The aftermath of the January 9, 2018 debris flows in Montecito, California.