A History of Research and a Review of Recent Developments

54
and 50%, rather than by a factor of 2, so a good deal of shock wave energy
was transmitted and dispersed on the bottom.
Surface waves can be generated by underwater explosions or by air bursts
close to the water surface. In the case of underwater explosions the outward
propagating waves result from the gas bubble breaking through the surface,
and in deep water explosions it is usually assumed that between 2% and 5% of
the yield of the charge is directed to the energy of the train of surface waves.
When the detonation is in relatively shallow water, there is often only an initial,
solitary wave, particularly for very large nuclear explosions. After the 20 kiloton
shallow water explosion at Bikini, mentioned earlier, wave heights and times of
arrival were recorded at increasing distances from the detonation point (surface
zero). At distances of 330, 2000 and 4000 yards the arrival times were 11, 74
and 154 seconds respectively, and the wave heights were 94, 16 and 9 feet.
Characteristic properties of the underwater shock wave from nuclear
explosions have been given by Glasstone and Dolan [2.9]. For water with no
reflections or refractions the relationship between peak instantaneous underwater
shock pressure in psi and the slant range in thousands of yards is given in Figure
2.21. Approximate relationships have been established for surface wave amplitude
(H) and radius (R) from surface zero for nuclear explosions as follows:
In deep water, 850 W 1/4 >d>256 W 1/4 , where W is yield in kilotons of TNT
equivalent, and d is water depth in feet,
where H and R are measured in feet.
In shallow water, d