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How is tsunami speed derived?

  1. Jan 12, 2005 #1
    I read that the speed of a tsunami is given by

    c = sqrt(G * d)

    where G is the gravitational constant 9.8 m/sec^2 and
    d is ocean depth in meters.

    How is this derived? I had always thought that wave speed was a constant depending only on the medium.

    Also, is there some fundamental mechanical difference between a tsunami and a "normal" surface ocean wave?
  2. jcsd
  3. Jan 12, 2005 #2
    Do you also know the formula for the height of the wave. (Of course in respect to the clifs stepping.)
  4. Jan 12, 2005 #3
    Hello lagrange,

    The behaviour of tsunami is the behaviour of shallow-water waves.
    Therefor the velocity of the waves is given by the equation for the shallow-water phase- and group velocity.

    Here you'll find the linear theory of ocean surface waves:

    The shallow-water velocity equation (16.8) and (16.11) in this paper are derived using the equations (16.5)and (16.6).

    More about ocean waves and tsunami:
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