Tsunami Information

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What is a Tsunami?

Tsunamis are ocean waves produced by earthquakes or underwater landslides. Tsunamis are often incorrectly referred to as tidal waves, but a tsunami is actually a series of waves that can travel at speeds averaging 450 (and up to 600) miles per hour in the open ocean. Tsunamis are extremely rare and have the potential to be extremely dangerous. When you hear a tsunami warning, it is best to stay clear of low lying coastal areas and never go to the beach to check it out. History shows that when these great waves finally strike land, it can leave a wake of destruction in its path.

What's the difference between a Tsunami Watch and a Tsunami Warning?

Tsunami Watch 

A tsunami watch is an alert issued to areas that might be impacted by a tsunami. An area included in the watch is based on the magnitude of the earthquake. A tsunami watch will either be upgraded to a warning or will be canceled depending on the severity of the tsunami. 

Tsunami Warning

A tsunami warning Indicates that a tsunami is imminent and that coastal locations in the warned area should be prepared. The initial warning is typically based on seismic information alone. Earthquakes over magnitude 7.0 trigger a warning covering the coastal regions within a two-hour tsunami travel time from the epicenter. When the magnitude is over 7.5, the warned area is increased to a three-hour tsunami travel time. As water-level data showing the tsunami is recorded, the warning will either be canceled, restricted, expanded incrementally or expanded in the event of a major tsunami.

Basic Tsunami Information



A sure sign of an approaching tsunamis is the noticeable rise or fall of coastal water. This is nature’s tsunami warning and should be heeded as a warning to clear the beach and get to higher ground.



A tsunami is not just a single wave, but a series of waves. The time between waves can be as long as 45 minutes. 



Between the waves, the water recedes away from the shoreline. Do not walk out further onto the sand. The next wave could approach at any time. Get to higher ground as soon as possible.



A small-wave tsunami at one beach can be quite different a few miles away. Do not be fooled into thinking you are safe.



All tsunamis are potentially dangerous, even though they may not damage every coastline they strike. 



Never go down to the beach to watch for a tsunami or attempt to surf a tsunami.



During a tsunami emergency, the Newport Beach Police, Fire, and Lifeguards will try to save your life. Give them your fullest cooperation and follow all emergency responders orders.



For more information on tsunamis, visit the National Oceanic and Atmospheric Administration's (NOAA) website.



Should a tsunami warning or watch be issued for our area, stay tuned to your AM/FM radio or television stations for information. You can also monitor bulletins issued by the National Weather Service and announcements from the City.






A tsunami is not just a single wave, but a series of waves. The time between these waves can be as long as 45 minutes. 

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