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 impact as a rapidly moving landslide mass enters the water or as water displaces behind and ahead of a rapidly moving underwater landslide. 

Research in the Canary Islands concludes that there have been at least five massive volcano landslides that occurred in the past, and that similar large events might occur in the future. Giant landslides in the Canary Islands could potentially generate large tsunami waves at both close and very great distances, and could potentially devastate large areas of coastal land as far away as the eastern seaboard of North America.

Rock falls and rock avalanches in coastal inlets, such as those that have occurred in the past at Tidal Inlet in Alaska's Glacier Bay National Park, have the potential to cause regional tsunamis that pose a hazard to coastal ecosystems and human settlements. On July 9, 1958, a magnitude 7.9 earthquake on the Fairweather Fault triggered a rock avalanche at the head of Lituya Bay, Alaska. The landslide generated a wave that ran up 524 meters (1,719 feet) on the opposite shore and sent a 30-meter-high wave through Lituya Bay, sinking two fishing boats and killing two people.

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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...

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...

What is the difference between a tsunami and a tidal wave?

Although both are sea waves, a tsunami and a tidal wave are two different and unrelated phenomena. A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. ("Tidal wave" was used in earlier times to describe what we now call a tsunami.) A tsunamis is an ocean wave triggered by large...

Is there a system to warn populations of an imminent occurrence of a tsunami?

NOAA (National Oceanic and Atmospheric Administration) maintains the U.S. Tsunami Warning Centers , which work in conjunction with USGS seismic networks to help determine when and where to issue tsunami warnings. If an earthquake meets certain criteria for potentially generating a tsunami, the pop-up window and the event page for that earthquake...

What are Tsunamis?

Tsunamis are ocean waves triggered by large earthquakes that occur near or under the ocean, volcanic eruptions, submarine landslides, and by onshore landslides in which large volumes of debris fall into the water. Scientists do not use the term "tidal wave" because these waves are not caused by tides. Tsunami waves are unlike typical ocean waves...

Could a large tsunami happen in the United States?

Large tsunamis have occurred in the United States and will undoubtedly occur again. Significant earthquakes around the Pacific rim have generated tsunamis that struck Hawaii, Alaska, and the U.S. west coast. One of the largest and most devastating tsunamis that Hawaii has experienced was in 1946 from an earthquake along the Aleutian subduction...
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Date published: September 18, 2015

Are American Cities Prepared For Massive Tsunamis?

Are American Cities Prepared For Massive Tsunamis?

Date published: May 20, 2014

Geologic Evidence of Past Tsunamis in California

An extensive sedimentary deposit formed by a tsunami in 1946 was recently discovered at Pillar Point Marsh near Half Moon Bay, California. While there were photos and eyewitness accounts of the tsunami and resulting damage at the time, finding the tangible evidence in the geologic record is an important part of assessing the long-term hazard of tsunamis on California coastal communities.

Date published: December 20, 2013

Earthquake/Tsunami Hazard in Caribbean Higher Than Previously Thought

Enough strain may be currently stored in an earthquake zone near the island of Guadeloupe to cause a magnitude 8 or larger earthquake and subsequent tsunami in the Caribbean, according to a new U.S. Geological Survey study.

Date published: May 27, 1998

USGS Scientist to Present Evidence for Cause of Caribbean Tsunamis a Boston Meeting

The Caribbean is not renowned for its potential to generate the huge waves known as "tsunamis" that often occur in the Pacific. And scientists worldwide refer to them by their Japanese name "tsunami", which means "harbor wave." Yet these long-period waves are not confined to the Pacific Ocean. 

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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.

January 26, 2017

PubTalk 1/2017 — Unusual sources of tsunamis

A presentation on "Unusual Sources of Tsunamis From Krakatoa to Monterey Bay" by Eric Geist, USGS Research Geophysicist

- Not all tsunamis are generated by earthquakes.
- Tsunamis can be caused by volcanoes, landslides, and even atmospheric disturbances
- Data from tide gauges can help unravel the complex physics of these sources

Videographers:

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New Zealand Landslides
December 31, 2016

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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Attribution: Landslide Hazards
Image shows a satellite view of Glacier Bay National Park with a landslide marked in yellow
September 14, 2016

Landsat View of Landslide in Glacier Bay

On August 7, the Operational Land Imager sensor aboard Landsat 8 captured the black stain of the landslide. Credit: USGS/NASA Landsat Program.

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
June 10, 2012

Landslide Hazards

Landslides occur in all 50 states and U.S. territories, and cause $1-2 billion in damages and more than 25 fatalities on average each year. USGS scientists aim to improve our understanding of landslide hazards to help protect communities and reduce associated losses.

 

 

 

Video Sections:

  • Types of Landslides
  • USGS Science
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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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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
depiction of the mechanics of a landslide
November 30, 2000

landslide graphic

graphic illustration of the parts of a landslide

Aerial view of the Mill Creek landslide blocking Highway 50.
January 24, 1997

Mill Creek landslide

Photo 1: Aerial view of the Mill Creek landslide blocking Highway 50.