I was recently asked to provide some information on Tsunamis. The Jefferson County Department of Emergency Management provided the following:
A strong earthquake felt in a low-lying coastal area is a natural warning of possible danger. Keep calm and quickly move to higher ground away from the coast.
All large earthquakes do not cause tsunamis. If the quake is located near or directly under the ocean, the probability of a tsunami increases. When you hear that an earthquake has occurred in the ocean or coastline regions, prepare for a tsunami emergency.
Tsunamis can travel up rivers and streams that lead to the ocean.
A tsunami is not a single wave, but a series of waves. Stay out of danger until an "ALL CLEAR" is issued.
Approaching tsunamis are sometimes heralded by noticeable rise or fall of coastal waters. This is nature's tsunami warning and should be heeded.
Approaching large tsunamis are usually accompanied by a loud roar that sounds like a train or aircraft.
A small tsunami at one beach can be a giant a few miles away. Local conditions may vary. Do not presume that no damage in one area indicates no damage in your warning area.
In some areas, lateral currents (parallel to the beach) can occur and are as dangerous as waves on shore.
Tsunami surges carry large amount of debris that can cause major damage.
Sooner or later, tsunamis visit every coastline in the Pacific. All tsunamis - like hurricanes - are potentially dangerous even though they may not damage every coastline they strike.
Never go to the beach (or cliff side) to watch for a tsunami! WHEN YOU CAN SEE THE WAVE YOU ARE TOO CLOSE TO ESCAPE. Tsunamis can move faster than a person can run!
Homes and other buildings located in low lying coastal areas are not safe. Do NOT stay in such buildings if there is a tsunami warning.
The upper floors of high, multi-story, reinforced concrete hotels can provide refuge if there is no time to quickly move inland or to higher ground.
If you are on a boat or ship and there is time, move your vessel to deeper water (at least 100 fathoms).
NOAA Weather Radio will provide initial warnings but will not give ongoing information. Tune to radio or television stations during a tsunami emergency - bulletins will be issued through the local emergency management office and National Weather Service offices.
If an evacuation order is made, an area higher than 50 feet above sea level is recommended. Stay away from soft banks that might be eroded by the wave action at the shoreline.