<P> The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion . For water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion above . </P> <P> In seawater, the water particles are moved in a circular orbital motion when a wave passes . The radius of the circle of motion for any given water molecule decreases exponentially with increasing depth . The wave base, which is the depth of influence of a water wave, is about half the wavelength . </P> <P> At depths greater than half the wavelength, the water motion is less than 4% of its value at the water surface and may be neglected . </P>

The depth of the wave base is approximately