TsunamiTeacher USA – Tsunami Basics


Welcome to TsunamiTeacher USA’s Tsunami Basics.
This short video is intended to provide you with the basic understanding of tsunamis and
how to protect yourself.>>EYE WITNESS ACCOUNT (Translated): On the
morning of September 29th, as you have asked, around six o’clock in the morning they felt
an earthquake occur. Knowing from previous training that I had received as a Mayor, we
waited up in the higher area. In the next several minutes you will learn,
What a tsunami is? How to recognize dangerous tsunami waves are
coming And what to do if you are in a tsunami hazard
or evacuation zone. Tsunamis are a series of traveling waves often
generated by earthquakes. In the deep ocean, the waves can be up to
hundreds of miles long yet only a few inches or a foot in height. So, if you are on a boat
in the deep ocean, you might not notice a tsunami wave passing beneath you. As they approach the shallow coast, the wave
heights will increase, and in extreme cases can be up to one hundred feet high when they
crash on shore. Tsunami waves travel very fast in the deep
ocean somewhere between four hundred and five hundred miles per hour, which is the speed
of a commercial jet airplane. In this animation of the September 2009 Samoa earthquake and
tsunami, waves took only ten to fifteen minutes to reach the coasts of American Samoa, Samoa
and Tonga and later reached California in about ten hours.>>EYE WITNESS ACCOUNT (Translated): Immediately
we know the earthquake is so strong that a tsunami may follow, and it is going to occur
just like the blinking of an eye, so please head for higher ground. A wave’s energy can focus flooding inland,
along a road, or up a river. Large debris, such as cars and trees, act as battering rams
causing destruction as the wave moves inland or recedes. The series of waves can continue
to arrive every five to sixty minutes for several hours. The next wave can arrive before
the previous one recedes resulting in greater water heights and further flooding inland.
The first wave also may not be the largest. These images give you an idea of what tsunami
waves may look like to a person on the shoreline. The waves arrive as walls of water, not as
typical breaking or curling wind or surf waves. At the coast, a tsunami wave will slow down
but the waves are still dangerous. This footage of the 2009 Samoa tsunami shows the ease with
which a tsunami wave less than one to two feet high moved cars. Remember, even small tsunamis can be extremely
dangerous to swimmers and boats in harbors due to the strong wave currents. If you see the ocean withdraw out to sea,
exposing the ocean bottom or hear the train-like roar of the tsunami, you might have less than
a minute to get to safety. When an earthquake occurs near the coast,
there may be only minutes before tsunami waves arrive. In this case, the natural warning
signs are your alert to act immediately. Strong coastal earthquakes that shake for
more than thirty seconds serve as a natural warning. Protect yourself first. Drop, cover,
and hold on until the shaking stops. When it is safe, survey the area around you and
evacuate by quickly walking inland and to higher ground. If wave arrival is imminent, consider vertical
evacuation to the highest floors of a multi-story reinforced concrete building.>>EYE WITNESS ACCOUNT (Translated): I looked
down at the ocean and I saw the ocean was receding. It was going out. I could see the
bottom of the ocean, the floor of the ocean. I knew then that the tsunami was coming. These images show the first tsunami wave after
it receded at Pago Plaza. The next wave inundating Pago Plaza arrived within ten minutes of the
preceding wave.>>EYE WITNESS ACCOUNT (Translated): I could
hear the wave was coming, and I felt it. This is a video of a small tsunami generated
by an iceberg breaking apart. You will notice small waves are generated followed by a loud
roar produced by the waves. The tsunami then lifts up fishing boats and relentlessly smashes
them onto the shore. [ROAR OF WAVES, PEOPLE SHOUTING] All coastlines are vulnerable to tsunamis.
Make sure you know your community tsunami hazard and evacuation zone. Walk your tsunami evacuation routes so you
know where they are located. Remember, in a local event the natural warning signs are
your earliest and possibly only alert. The US’s West Coast Alaska Tsunami Warning
Center and Pacific Tsunami Warning Center are monitoring earthquakes all the time and
will issue official warnings but they may not be in time to warn for a local tsunami.
So, do not wait for the official warnings. Based on the tsunami’s natural warning signs,
act immediately.>>EYE WITNESS ACCOUNT (Translated): Immediately
we know the earthquake is so strong that a tsunami may follow, and it’s going to occur
just like the blinking of an eye, so please head for higher ground. [SLOSHING OF WAVES]

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