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Safety & Prevention

Tsunami Disaster Fact Sheet

What is a Tsunami?

Tsunamis are ocean waves produced by earthquakes or underwater landslides. The word is Japanese and means “harbor wave,” because of the devastating effects these waves have had on low-lying Japanese coastal communities. Tsunamis are often incorrectly referred to as tidal waves, but a tsunami is actually a series of waves that can travel at speeds averaging 450 (and up to 600) miles per hour in the open ocean.

Why Talk About Tsunamis?

Tsunamis have caused damage in the United States and its territories. As a tsunami nears the coastline, it may rise to several feet or, in rare cases, tens of feet, and can cause great loss of life and property damage when it comes ashore.

Tsunamis can travel upstream in coastal estuaries and rivers, with damaging waves extending farther inland then the immediate coast. A tsunami can occur during any season of the year and at any time, day or night.

What Can I do to Prepare for a Tsunami?

In addition to completing the 4 Steps to Safety, do the following:

  • Learn about tsunami risk in your community. Contact your local emergency management office or American Red Cross chapter.
  • If you are visiting an area at risk from tsunamis, check with the hotel, motel, campground operators for tsunami evacuation information and how you would be warned.
  • Plan an evacuation route from your home, school, workplace, or any other place you’ll be where tsunamis present a risk.

What to do When a Tsunami watch is Issued

  • Listen continuously to a NOAA Weather Radio, or a portable battery-powered radio (or television) for updated emergency information.
  • Check your disaster supplies kit.
  • If time permits, secure unanchored objects around your home or business.
  • Be ready to evacuate.

What to do When a Tsunami Warning is Issued

  • If you hear an official tsunami warning or detect signs of a tsunami, evacuate at once.
  • A tsunami warning is issued when authorities are certain that a tsunami threat exists, and there may be little time to get out.
  • Take your Family Readiness Kit and your disaster supplies.
  • Go to higher ground as far inland as possible.

What to do After a Tsunami

  • Continue listening to local radio or television stations or a NOAA Weather Radio for updated information and instructions.
  • Help neighbors who may require special assistance.
  • Avoid loose or dangling power lines and report them to the power company, police or fire department.
  • Stay out of damaged buildings.
  • Wear sturdy shoes.
  • Check for fire hazards.
  • Check for gas leaks.
  • Use the telephone for emergency calls only.
Last Updated
Family Readiness Kit: Preparing to Handle Disasters, 2nd Edition
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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