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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.
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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. Most tsunamis are caused by undersea earthquakes, as shown here, but they can also be caused by landslides, volcanic activity, and even meteorites. 1 2 3 4 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. http://www.tsunami.noaa.gov/
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 http://1.usa.gov/1gxKbFm
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 Vega Baja, Puerto Rico Crescent City, California http://www.tsunami.noaa.gov/
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: http://ntwc.arh.noaa.gov/ NOAA Weather Radio All Hazards http://www.nws.noaa.gov/nwr/ http://www.tsunami.gov/
Tsunami Preparedness Week 1964 Great Alaska Earthquake and Tsunamis http://1.usa.gov/1gCxptu Credit: NOAA
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 http://1.usa.gov/1hwqfVD