Tsunami Awareness

Tsunamis - Knowing more about them really can save your life

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    NEWSLETTERS

    Dominic Ferrigno
    A user sent us some dramatic images showing the effect of last weekend's tsunami advisory on our coastline. It's a sequence of four photos taken from 3:15 to 3:45 p.m. Saturday from Sunset Cliffs.

    It's one thing to learn how to spell "Tsunami" but do you really know what it is and, more importantly, how to respond if one is headed your way? 

    We're in the middle of Tsunami Awareness Week and this is as good a time as any to become an expert.  Not doing so is dangerous and could be deadly - yes, even here in San Diego.

    Tsunamis used to be known as "tidal waves" and most people probably thought of them only as isolated, giant walls of ocean that suddenly appeared out of nowhere destroying everything in their path. As we've seen in recent years they can be very destructive and quite deadly but, what we've also learned is that just about anywhere there is a coastline there is the potential of a tsunami.

    Tsunamis are generally caused by earthquakes like the 2004 9.1- magnitude Sumatran quake that caused a number of large waves to smash into 14 different countries causing millions of dollars in damage and killing nearly 230,000 people.  Researchers believe that some of those waves were 100 feet tall when they came ashore.

    Strong "super quakes" such as that one generate massive energy that literally "pushes" vast amounts of water towards land.  As the depth of the ocean becomes shallower as this "energy" nears a coastline, two things happen.  One is the formation of unusually large, devastating waves - the other is an extreme "tidal surge", much like what we see with a hurricane. This is where a large amount of seawater is pushed much further inland than normal; the higher the surge and flatter the land mass, the greater the damage and potential loss of life.

    Imagine the Pacific Ocean suddenly becoming 10' or even 4' deeper than at the highest tide.  With enough sustained energy behind it it could roll right up over, say the boardwalk at Mission Beach, ending up in Mission Bay or the La Jolla Cove -  just think of the damage that would occur if the ocean moved up over the beach at The Shores and rolled through the low-lying neighborhoods there.

    Two warning systems are in place to make you aware of an approaching Tsunami.  There is a high-tech system of off-shore buoys that constantly read the strength of the oceans currents and energy and send signals to receivers on-shore that, in the case of an emergency would notify those on land through loud, shrill sirens as well as broadcasting alerts over the radio and television stations.  The other warning system is nature itself.  If you feel a strong earthquake and are anywhere near the water you should move to higher ground.  Another tell-tale sign that a Tsunami is coming is the rapid receding of the ocean away from the beach.

    To learn more about Tsunamis and Awareness Week, click here to link to NOAA's website: http://nthmp.tsunami.gov/tsunamiweek.html