Tsunamis are large seismic waves caused by volcanic eruptions or earthquakes that occur at the bottom of the ocean. Tsunamis move at a rapid rate of speed, up to one hundred miles an hour, and create waves 100 feet or higher that often hit coastal areas.
Tsunami waves travel in every direction from the source of origination. As waves reach the coast, they increase in height. Wave size and height are affected by coastline topography. During a tsunami, initial waves are often smaller than later ones. As a result, a beach can be hit with relatively small waves, while one a few miles from it can be hit with very large waves.
Every tsunami can cause property damage and casualties, regardless of whether they cause damage to coastlines near where the tsunami originates. Tsunamis are a potential hazard near every U.S. coastline. Deadly tsunamis have hit the Hawaiian, Washington, Alaskan, Oregon, and California coasts.
Tsunamis can be the result of landslide, volcanic eruption, or meteorites but are usually created by ocean floor earthquakes. Once an earthquake occurs at the ocean’s floor, initial waves often hit the shore within minutes. Regions that are 25 feet or lower below sea level typically receive the brunt of a tsunami. Most people killed during a tsunami drown. Buildings within the run-up zone are often destroyed by large waves and receding water. In addition to damage caused by large waves, fires caused by leaking gas and flooding destroy property. Contaminated water poses a major threat to human health after a tsunami.
What to Do Before a Tsunami Hits
The following are things you can do to protect yourself, your family and your property from the effects of a tsunami:
- To begin preparing, you need to build a emergency kit and make a family communications plan.
- Discuss with family members and friends what should be done if a tsunami hits your hometown. Develop an evacuation plan and practice it with family members. Although this may be time consuming and burdensome, it could save the lives of you and your family. Be sure to practice at night and during bad weather. Practice your escape plan until you and your family can reach the designated safe area with 15 minutes. Practicing your plan will cause you to act on instinct, making it easier to remain calm during an actual tsunami.
- Develop a plan to pick children up from school since phone lines might be down and roads will be crowded during a tsunami evacuation order.
- Learn about and become familiar with your city’s disaster plans and evacuation routes.
- Know the exact distance of your home from the beach and the elevation above sea level since local communities usually base evacuation orders on these figures.
- If you plan on visiting a region that is at risk of a tsunami, learn about local evacuation procedures. The upper stories of concrete reinforced high-rise hotels are typically safe places to find refugee during tsunamis.
- If you are in a coastal region during an earthquake, make sure to listen to radio and TV broadcasts for tsunami warnings.
What to Do During a Tsunami
- Evacuate immediately with pets after an evacuation order.
- Relocate a safe distance from the coast to higher ground. Find a location 2 miles from the shore and 100 feet or more above sea level. If it’s not possible to find such a location, travel as far from the shore as possible. Even the slightest variations in distance and altitude make a difference.
- Avoid the beach if a tsunami warning is issued. Visible waves are too close to run from. Be cautious of receding water from the beach since it is a sign that a tsunami is imminent. Leave the area immediately.
- Don’t worry about gathering material possessions. Your life is more important.
- Assist neighbors and friends with special needs, such as the elderly, disabled individuals, infants, and others.
What to Do After a Tsunami
- Return to your house after local officials have authorized it. Tsunamis often last for hours. A subsequent series of waves often follow the first wave. Do not assume it is safe because waves are not visible.
- If you’re unable to return home, stay in a public shelter. Text SHELTER + your ZIP code to 43362 (4FEMA) to locate the closest shelter in your region (example: shelter 87112).
- Stay away from disaster regions. You might get in the way of rescue personnel, and you will more than likely be in a region at risk of floods.
- Avoid debris floating in the water. It could pose a safety threat to people or animals.
- Determine if you have any injuries and seek medical attention immediately before assisting trapped or other injured individuals.
- If you locate someone that is trapped or injured, call emergency specialists with the proper rescue equipment right away. People are sometimes seriously injured or killed while attempting to rescue others.
- Assist individuals with special needs, including the elderly, infants, individuals without transportation, people with large families, and the disabled that may require extra assistance during an emergency.
- Listen to local radio or TV broadcasts, NOAA Weather Radio broadcasts or a Coast Guard Station for the latest information.
- Avoid buildings that are surrounded by water. Flood water often causes walls to collapse or crack.
- Be careful while re-entering houses or buildings. Tsunami flood water often creates unexpected structural damage. Use caution wherever you step in the building.
- During cleanup, wear protective gear to prevent injuries.
Last update 2020-10-22. Price and product availability may change.