[Orchestra Music]
- Hey there, this is Brain
Stuff and I'm Josh Clark,
and this is the Brain Stuff
where I explain to you
how tsunamis work.
The word tsunami actually
comes from two Japanese words,
"tsu," meaning harbor,
and "nami," meaning waves.
Basically, when you put
them together it means that
when these waves hit the harbor, brother,
you better get out of there.
There are some differences
between a tsunami wave
and a regular Joe Schmo wave,
but any wave is actually
an energy carrier.
We tend to think of waves as
water moving through itself,
but actually waves are
energy moving through water.
The difference between a
tsunami wave and a regular wave
is how that energy is
transferred, and how much energy
that wave packs.
So the ordinary, typical,
Joe Schmo, surfer dude wave
propagates from wind
blowing across the surface
of the ocean.
Well, Buckminster Fuller pointed
out that the wind actually
sucks, it doesn't blow,
but that's a different
Brain Stuff episode entirely.
A tsunami wave, however, is
propagated by some sort of
underwater disturbance.
These are called "tsunamigenic events."
So things like an
underwater rock slide, or an
underwater earthquake,
or an underwater volcano
can all set off a tsunami.
So think of a rock pile or
a couple of tectonic plates
sliding against each other on a fault line
as possessing a ton of stored energy.
We call this "potential energy."
Now when one tectonic plate suddenly slips
beneath the other, this
potential energy is released
as kinetic energy.
This energy is transferred
outward from the point of origin
in much the same way as when
you take a rock or a pebble
and throw it into a pond.
It creates ripples, right?
Well, with a tsunami these
ripples, waves, radiate
from the point of origin
traveling at hundreds of miles
an hour, carrying with
them a lot of energy.
Now if you're watching a tsunami
wave out in the deep ocean,
what you're gonna see is
about a three foot tall wave
traveling really, really fast.
But what you're seeing,
metaphorically speaking,
is just the tip of the iceberg.
This incredibly deep ocean
wave that's traveling so fast
encounters, ultimately, the shoreline.
The shoreline that slopes
upward compresses the energy
of the tsunami wave.
It slows its velocity down
tremendously, but it also
forces it upward, so what
once was a three foot wave
is now something like a
hundred feet, and it's
at the shore.
One of the big misconceptions
about tsunamis is that
they exist as just one wave,
but remember they're a lot
like a pebble created by a
rock tossed into the pond.
A bunch of ripples are created.
When the first tsunami
waves reach the shoreline
and slow down, the waves in
the rear start to catch up.
They compress, forming what's known as a
"tsunami wave train."
Since tsunamis pose such a
danger, scientists are constantly
trying to figure out
how to deal with them.
The thing is, is since we're
talking about such a huge
release of kinetic energy,
once a tsunami starts,
there's no stopping it.
So the best science can hope
for is to predict their path
and power so they can warn
coastal areas to clear out
as soon as possible.
Have you ever seen a tsunami?
Let us know in the comments
below, and while you're
down there, go ahead and subscribe.
And for even more great videos,
go to brainstuffshow.com.
