Tsunami Preparedness Week

Tsunami Preparedness Week

http://www.tsunami.noaa.gov/

How a Tsunami Works

An underwater earthquake occurs when a plate shifts abruptly and pushes water upward with tremendous force.

Low and fast waves are generated in all directions across the ocean, some speeding as fast as 600 mph.

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As waves enter shallower water, they are compressed, their speed slows, and they build in height.

The wave height increases, and associated currents intensify, becoming a threat to life and property.

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Most tsunamis are caused by undersea earthquakes, as shown here, but they can also be caused by landslides, volcanic activity, and even meteorites.

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Know Your Risk

Tsunami risk is greatest around the Pacific Basin. Volcanic arcs (orange) and oceanic trenches (blue) make up the Pacific Ocean basin’s Ring of Fire, an area prone to earthquakes that may trigger tsunamis.

Credit: U.S. Geological Survey

Tsunami Preparedness Week

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Know Your Risk

Examples of tsunami evacuation maps

Ask your local or state emergency management office or your local National Weather Service office to learn about your community’s tsunami risk.

Vega Baja, Puerto RicoCrescent City, California

Tsunami Preparedness Week

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Tsunami Messages

Advisory: A tsunami with potential for strong currents or waves dangerous to those in or very near the water is imminent, expected, or occurring. Significant inundation is not expected.

Information Statement: An earthquake has occurred, or a tsunami warning, watch, or advisory has been issued for another section of the ocean. In most cases, an information statement indicates there is no threat of a destructive tsunami in your area.

Watch: A potentially dangerous distant seismic event has occurred that may later impact the watch area with a tsunami.

Warning: A tsunami with potential for widespread inundation is imminent, expected, or occurring. Dangerous coastal flooding and powerful currents are possible and may continue for several hours after initial arrival.

Warning: Watch:

Advisory:

Information Statement:

Adapted from: http://ntwc.arh.noaa.gov/

NOAA Weather Radio All Hazards http://www.nws.noaa.gov/nwr/

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1964 Great Alaska Earthquake and Tsunamis

Credit: NOAA

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Tsunami Safety⁻ Danger!

⁻ Run for high ground

⁻ Follow emergency instructions

⁻ Potential danger

⁻ Stay tuned for more information

⁻ Possible dangerous currents

⁻ Move off the beach & stay out of the water

⁻ Relax

⁻ No local danger

⁻ A distant ocean basin may be in danger

WARNING

WATCH

INFORMATION STATEMENT

ADVISORY

Tsunami Preparedness Week