|What are the stages or steps of a tsunami?
|Question Date: 2017-11-28|
A tsunami has four general stages: initiation,
split, amplification, and run-up.
During initiation, a large set of ocean
waves are caused by any large and sudden
disturbance of the sea surface, most commonly
earthquakes but sometimes also underwater
In the split stage, the initial set of
waves is split into two, one set that travels out
into the deep ocean and another that travels
toward a nearby coast.
In stage three, amplification, the
height of the tsunami increases, and the
distance between two adjacent crests (high points)
as it travels toward the coast, so the first wave
of the tsunami becomes steep.
In the last stage, a peak of the tsunami
hits shore . The reason this stage is
called the run-up stage is that run-up is the
term used to describe the measurement of the
height of the water on the shore . Once on
land, part of the tsunami is reflected back into
the ocean, and another part is trapped in waves
that travel back-and-forth near the shore.
Tsunamis are ocean waves with a very long
period, or distance between wave crests. These
waves form when a large amount of water is
displaced, for example by a landslide into the
ocean, or by an earthquake that moves the
seafloor. The energy associated with the
displacement of water (potential energy) is turned
into a wave (kinetic energy).
After the water is displaced, the tsunami
waves travel away from their source area.
They have a low amplitude (height), but they
travel extremely fast. In deep water, tsunamis
pose no risk: you would almost certainly not feel
a tsunami wave on a boat in the deep ocean. As
the tsunami wave reaches shallower water, however,
the wave slows down and the wave height
increases. This process generates the
potentially devastating waves that we associate
with tsunamis. Tsunamis are associated both
with large waves, and with moving a large
volume of water onto land.
For a tsunami to form there has to be a source of
energy to move the ocean water to create tsunami
waves. Usually earthquakes, and sometimes
underwater landslides, can give the water enough
of a push to make a large tsunami.
A tsunami will
then move quickly over open water. When the waves
are moving across the open ocean the tsunami
usually isn't so high. However, once the waves
move towards shallower water the waves will grow
until they hit land, but they will also slow down
A tsunami is basically a pressure wave that causes
a body of water to overflow its shores.
To give an example, take a bath. While lying with
most of your body under water, raise your hand
above the water. Then, suddenly, drop your hand
under the water. You will notice a small wave
extend out from where your hand was above the
surface, and that wave will cause the water level
of the tub to go up and down when the wave hits
the edge of the tub. This wave is a very small
tsunami. The reason why tsunamis in the ocean are
so deadly is because instead of the source being
the movement of something the size of your fist,
it is instead something the size of a mountain (or
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