1. Tsunami Preparedness Week
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. 1 2
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. 3 4
Most tsunamis are caused by undersea earthquakes, as shown here, but they can also be caused by landslides, volcanic activity, and even meteorites.

2. Tsunami Preparedness Week
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

3. Tsunami Preparedness Week
Know Your Risk
Ask your local or state emergency management office or your local National Weather Service office to learn about your community’s tsunami risk.
Examples of tsunami evacuation maps
Crescent City, California
Vega Baja, Puerto Rico

4. Tsunami Preparedness Week
Tsunami Messages
Warning:
Watch:
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.
Watch: A potentially dangerous distant seismic event has occurred that may later impact the watch area with a tsunami.
Information Statement:
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.
Advisory:
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.
Adapted from:
NOAA Weather Radio All Hazards

5. 1964 Great Alaska Earthquake and Tsunamis
Tsunami Preparedness Week
1964 Great Alaska Earthquake and Tsunamis
Credit: NOAA

6. INFORMATION STATEMENT
Tsunami Preparedness Week
Tsunami Safety
WARNING
Danger!
Run for high ground
Follow emergency instructions
ADVISORY
Possible dangerous currents
Move off the beach & stay out of the water
WATCH
Potential danger
Stay tuned for more information
INFORMATION STATEMENT
Relax
No local danger
A distant ocean basin may be in danger

7. Tsunami Preparedness Week