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Tsunamis are destructive waves caused by sudden displacement of ocean water. Tsunamis most often appear on shore as a rapidly receding tide or rapidly rising flood. In the United States, the Pacific coastal states – Oregon, Washington, California, Alaska, and Hawaii – are at greatest risk for destructive tsunamis.


Inundation at Pago Pago, American Samoa, from the 2009 Samoa tsunami. Image Credit: NOAA/NGDC

A tsunami is a series of waves formed in a body of water by the sudden displacement of the entire water column. Most large tsunamis are caused by undersea earthquakes, though landslides, volcanic eruptions, explosions, and even meteorite impacts can also cause them. Tsunamis commonly appear on shore as a rapidly receding tide or rapidly rising flood. Tsunamis sometimes provide natural warning signs to people living on coasts, especially close to the tsunami-causing event, such as a rapidly receding tide prior to the waves' arrival. Global monitoring systems also provide critical early warning to coastal populations.[1]   Read more

Frequently Asked Questions

American Geosciences Institute
National Oceanic and Atmospheric Administration

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...
April 6, 2017 The Hazards Caucus Alliance, a network that supports the Congressional Hazards Caucus, hosted a briefing on April 6 about how geologic and hazards mapping and monitoring are used to prepare and protect communities from natural hazards. The Hazards Caucus provides congressional staff...
Cracked road from earthquake
March 27, 2017 The Pacific Northwest Earthquake Preparedness Act (H.R.654) moved a step closer to becoming law when the bill passed the House on March 27. Representative Pete DeFazio (D-OR-4) introduced H.R.654 on January 24. The bill would establish an earthquake and tsunami inter-agency task...
IES Oceans Glyph
January 10, 2017 Rep. Suzanne Bonamici (D-OR-1) introduced the Tsunami Warning, Education, and Research Act (H.R. 312) on January 10. This bill directs the National Oceanic and Atmospheric Administration (NOAA) to strengthen tsunami research, detection, forecasting, warning, and mitigation programs...
Cracked road from earthquake
November 10, 2016 On November 10, the National Academy of Sciences (NAS) hosted a panel discussion on the Cascadia Subduction Zone (CSZ) and its potential for large scale fault rupture. Research from a number of academic institutions has suggested that such a rupture is capable of producing a...
Screenshot of a graphic showing the Cascadia Subduction Zone
On Thursday November 10, The National Academies' Board on Earth Science and Resources and the Committee on Seismology and Geodynamics held a joint meeting on The Cascadia Subduction Zone: Science, Impacts, and Response. The meeting provided a forum for the discussion of progress and future...
#MapOfTheDay! Check out this interactive map of estimated tsunami travel times: bit.ly/1QTKEY9 #TsunamiDay2016 @NOAA
#MapOfTheDay! Tomorrow is World Tsunami Awareness Day, so today the Critical Issues Program (@AGI_GeoIssues) shared an interactive map of estimated tsunami travel times to coastal locations from the National Oceanic and Atmospheric Administration (@NOAA), which you can find at http://bit.ly/1QTKEY9...
IES Oceans Glyph
February 26, 2015                                                              The Senate Commerce, Science, and Transportation Committee marked up and passed the Tsunami Warning, Education, and Research Act of 2015 (H.R.34) on February 26. The legislation reauthorizes programs that support tsunami...
NASA hurricane satellite image
January 7, 2015 On January 7, the House passed two bills that focus on research and preparedness for tsunami and windstorm hazards. The Tsunami Warning, Education, and Research Act (H.R.34) introduced by Rep. Suzanne Bonamici (D-OR) reauthorizes programs that support tsunami forecasting and coastal...
Atlantic waves
September 8, 2014 On September 8, the House of Representatives passed the Tsunami Warning, Education, and Research Act (H.R. 5309) by voice vote. Introduced by Representatives Susan Bonimici (D-OR) and Dana Rohrbacher (R-CA), H.R. 5309 would reauthorize the National Tsunami Hazard Mitigation...

GOLI Online Courses

GOLI Course: Communicating Cascadia's Earthquake Risk. Image Credit: FEMA / Photo by Mustafa Lazkani
Course Type: GOLI Online Course

Geoscience research is at the forefront of characterizing the earthquake risks associated with the Cascadia subduction zone in the Pacific Northwest. This course covers the science and its implications for policy decisions and resiliency efforts.

Research Database Publications

Cover of sir20165053; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
Hawai'i has experienced numerous destructive tsunamis and the potential for future inundation has been described over the years using various historical events and scenarios. To support tsunami preparedness and risk-reduction planning in Hawai'i, this study documents the variations among 91 coastal...
Local Planning Guidance on Distant Tsunami Response, Oregon Geological Survey
2012, Oregon Department of Geology and Mineral Industries (DOGAMI)
On average, Oregon receives about one distant tsunami warning, advisory, or watch per year. This Guidance Document, from the Oregon Distant Tsunami Working Group, is intended to ensure that there is a standardized response in order to protect life and property. Response to a distant tsunami is...
Grimsvötn on May 22, 2011.
2014, American Geosciences Institute (AGI)
When Grimsvötn Volcano in Iceland erupted in May 2011, northern European airspace was closed for seven days and about 900 passenger flights were canceled. Scientists were charged with trying to read the volcano — to tell how high the ash plume would go and to figure out how long the violent...
Cover of RI2015_001; Source Alaska Department of Natural Resources, Division of Geological and Geophysical Surveys
2015, Alaska Division of Geological & Geophysical Surveys (AK DGGS)
In this report, we evaluate potential tsunami hazards for southeastern Alaska communities of Elfin Cove, Gustavus, and Hoonah and numerically model the extent of inundation from tsunami waves generated by tectonic and landslide sources. We perform numerical modeling of historic tsunami events, such...
Cover of MTRG-2015-OR-01; Source: Oregon Department of Geology and Mineral Industries (DOGAMI)
2015, Oregon Department of Geology and Mineral Industries (DOGAMI)
Distant tsunamis are caused by great earthquakes far away from the Oregon coast and will strike approximately 4 hours or more after the earthquake and cause water level and current changes for many hours after first arrival. This document provides response guidance in the event of a distant tsunami...
A library in California following an earthquake. Image Copyright © California State University Northridge Geology Department, Image source: Earth Science World Image Bank http://www.earthscienceworld.org/images
2012, American Geosciences Institute (AGI)
A year ago this month, a devastating earthquake and tsunami struck northern Japan. Two years and two months earlier, on Jan. 12, 2010, a much smaller earthquake devastated Haiti. Both earthquakes occurred on a weekday and in the afternoon, but there is very little else that is similar about these...
Cover of factsheet; Image credit: Hazards Caucus Alliance
2009, Hazards Caucus Alliance (HCA)
A tsunami is generated when a large volume of water is rapidly displaced, usually as a result of a submarine or coastal earthquake—though marine landslides, volcanic eruptions, nuclear weapons testing, and asteroid impacts can all potentially create tsunamis. All coastal states have a tsunami risk...
Cover for USGS FS 2014-3018 ; Source: USGS
2014, U.S. Geological Survey (USGS)
The magnitude 9.2 Great Alaska Earthquake that struck south-central Alaska at 5:36 p.m. on Friday, March 27, 1964, is the largest recorded earthquake in U.S. history and the second-largest earthquake recorded with modern instruments. The earthquake was felt throughout most of mainland Alaska, as...