In shallow water (0-80 ft), what percentage of the shockwave reaches the surface?

In shallow water (0-80 ft), what percentage of the shockwave reaches the surface?

• A. 0% of the shockwave reaches the surface.
• B. 100% of the shockwave reaches the surface.
• C. 50% of the shockwave reaches the surface.
• D. 25% of the shockwave reaches the surface.

Answer: (B)

In shallow water, the upward-moving portion of an underwater shockwave has only a short distance to travel before it reaches the surface, so there’s little opportunity for attenuation from spreading or absorption. The water–air boundary does not drain most of that energy into air due to the large impedance mismatch, but that doesn’t change the fact that the surface is struck by nearly the full upward-directed shock energy. So, the shockwave energy that is directed toward the surface reaches it essentially intact, i.e., 100%.

In shallow water, the upward-moving portion of an underwater shockwave has only a short distance to travel before it reaches the surface, so there’s little opportunity for attenuation from spreading or absorption. The water–air boundary does not drain most of that energy into air due to the large impedance mismatch, but that doesn’t change the fact that the surface is struck by nearly the full upward-directed shock energy. So, the shockwave energy that is directed toward the surface reaches it essentially intact, i.e., 100%.