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海啸

拍击海岸的海啸大浪

以身作则，动员他人行动起来， 承诺进行准备，并告诉其他人这意味着什么！

承诺进行准备

海啸（发音为 soo-ná-mees），也称为地震海啸（曾被误称为"浪潮"），是诸如 地震, 山体滑坡, 火山爆发或陨石坠落这样的水下扰动产生的一系列大浪。 在开阔的洋面上，海啸能以每小时数百英里的速度前进，以高达 100 英尺的大浪冲击陆地。

从海啸的发源地开始，大浪沿各个方向向外前进。 一旦波浪抵达海岸，就会高高立起。 海岸线和海底的地形决定海浪的大小和高低。 大浪可能不止一个，后面的一个可能还大过前面这个。 这就是为什么一个海滩上的小型海啸，在数英里之外的另一个海滩可以变成一庞然大物。

所有的海啸都有潜在危险，即便它们可能并没有摧毁它们袭击的每段海岸线。 海啸可以沿着美国大部分的海岸线袭击任何地方。最具破坏力的海啸发生在加利福尼亚、俄勒冈、华盛顿、阿拉斯加和夏威夷的海岸上。

地震引发的海底运动多半会引发海啸。 如果某个大地震或山体滑坡发生的地方靠近海岸，甚至在警报发出之前，一系列海浪中的第一个便会在数分钟内抵达海滩。 高于海平面不足 25 英尺、在海岸线一英里内的地方风险更大。 溺水是海啸中死亡发生的最常见原因。 海啸大浪和消退的洪水对过水地带上的建筑物极具破坏力。 其它危害包括 洪水, 饮用水污染和燃气管或油罐破裂引发的火灾。

Wreckage after a tsunamiBefore a Tsunami

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 should build an emergency kit and make a family communications plan.
    • Talk to everyone in your household about what to do if a tsunami occurs. Create and practice an evacuation plan for your family. Familiarity may save your life. Be able to follow your escape route at night and during inclement weather. You should be able to reach your safe location on foot within 15 minutes. Practicing your plan makes the appropriate response more of a reaction, requiring less thinking during an actual emergency.
    • If the school evacuation plan requires you to pick your children up from school or from another location. Be aware telephone lines during a tsunami watch or warning may be overloaded and routes to and from schools may be jammed.
    • Knowing your community's warning systems and disaster plans, including evacuation routes.
  • Know the height of your street above sea level and the distance of your street from the coast or other high-risk waters. Evacuation orders may be based on these numbers.
  • If you are a tourist, familiarize yourself with local tsunami evacuation protocols. You may be able to safely evacuate to the third floor and higher in reinforced concrete hotel structures.
  • If an earthquake occurs and you are in a coastal area, turn on your radio to learn if there is a tsunami warning.
Know the Terms

Familiarize yourself with these terms to help identify a tsunami hazard:

Warning

A tsunami warning is issued when a tsunami with the potential to generate widespread inundation is imminent or expected. Warnings alert the public that dangerous coastal flooding accompanied by powerful cur­rents is possible and may continue for several hours after initial arrival. Warnings alert emergency management officials to take action for the entire tsunami hazard zone. Appropriate actions to be taken by local officials may include the evacuation of low-lying coastal areas, and the repositioning of ships to deep waters when there is time to safely do so. Warnings may be updated, adjusted geographically, downgraded, or canceled. To provide the earliest possible alert, initial warnings are normally based only on seismic information.

Advisory

A tsunami advisory is issued when a tsunami with the potential to generate strong currents or waves dangerous to those in or very near the water is imminent or expected. The threat may continue for sev­eral hours after initial arrival, but significant inundation is not expected for areas under an advisory. Appropriate actions to be taken by local officials may include closing beaches, evacuating harbors and marinas, and the repositioning of ships to deep waters when there is time to safely do so. Advisories are normally updated to continue the advisory, expand/contract affected areas, upgrade to a warning, or cancel the advisory.

Watch

A tsunami watch is issued to alert emergency management officials and the public of an event which may later impact the watch area. The watch area may be upgraded to a warning or advisory - or canceled - based on updated information and analysis. Therefore, emergency management officials and the public should prepare to take action. Watches are normally issued based on seismic information without confirmation that a destructive tsunami is underway.

Information Statement

A tsunami information statement is issued to inform emergency manage­ment officials and the public that an earthquake has occurred, or that a tsunami warning, watch or advisory has been issued for another section of the ocean. In most cases, information statements are issued to indicate there is no threat of a destructive tsunami and to prevent unnecessary evacuations as the earthquake may have been felt in coastal areas. An information statement may, in appropriate situations, caution about the possibility of destructive local tsunamis. Information statements may be re-issued with additional information, though normally these messages are not updated. However, a watch, advisory or warning may be issued for the area, if necessary, after analysis and/or updated information becomes available.

During a Tsunami

  • Follow the evacuation order issued by authorities and evacuate immediately. Take your animals with you.
  • Move inland to higher ground immediately. Pick areas 100 feet (30 meters) above sea level or go as far as 2 miles (3 kilometers) inland, away from the coastline. If you cannot get this high or far, go as high or far as you can. Every foot inland or upward may make a difference.
  • Stay away from the beach. Never go down to the beach to watch a tsunami come in. If you can see the wave you are too close to escape it. CAUTION - If there is noticeable recession in water away from the shoreline this is nature's tsunami warning and it should be heeded. You should move away immediately.
  • Save yourself - not your possessions.
  • Remember to help your neighbors who may require special assistance - infants, elderly people, and individuals with access or functional needs.

After a Tsunami

  • Return home only after local officials tell you it is safe. A tsunami is a series of waves that may continue for hours. Do not assume that after one wave the danger is over. The next wave may be larger than the first one.
  • Go to a designated public shelter if you have been told to evacuate or you feel it is unsafe to remain in your home. Text SHELTER + your ZIP code to 43362 (4FEMA) to find the nearest shelter in your area (example: shelter 12345).
  • Avoid disaster areas. Your presence might interfere with emergency response operations and put you at further risk from the residual effects of floods.
  • Stay away from debris in the water; it may pose a safety hazard to people or pets.
  • Check yourself for injuries and get first aid as needed before helping injured or trapped persons.
  • If someone needs to be rescued, call professionals with the right equipment to help. Many people have been killed or injured trying to rescue others.
  • Help people who require special assistance—infants, elderly people, those without transportation, people with access and functional needs and large families who may need additional help in an emergency situation.
  • Continue using a NOAA Weather Radio or tuning to a Coast Guard station or a local radio or television station for the latest updates.
  • Stay out of any building that has water around it. Tsunami water can cause floors to crack or walls to collapse.
  • Use caution when re-entering buildings or homes. Tsunami-driven floodwater may have damaged buildings where you least expect it. Carefully watch every step you take.
  • To avoid injury, wear protective clothing and be cautious when cleaning up.

Related Websites

Find additional information on how to plan and prepare for a tsunami and learn about available resources by visiting the following websites:

Listen to Local Officials

Learn about the emergency plans that have been established in your area by your state and local government. In any emergency, always listen to the instructions given by local emergency management officials.