text: by the local flow changes at these surfaces. 
  Of course, the strength of the shock waves 
  and the pressure jump 
  the wave 
  decreases rapidly with distance away from the 
  the pressure jump through 
  airplane. While 
  the shock wave decreases with distance away 
  from the surface, it does not disappear com- 
  pletely and a measurable-but very small- 
  pressure will exist at a considerable distance 
  from the airplane. 
  
  through 
  
  The intensity of the boom will depend on 
  many different factors. The characteristics of 
  the airplane generating the shock waves will 
  be of some importance since a large, high drag, 
  high gross weight airplane in flight at high 
  Mach number will be transferring a greater 
  energy to the air mass. Flight altitude will 
  have an important bearing on boom intensity 
  since at high altitude the pressure jump across 
  In addition, 
  a given wave form is much less. 
  at high altitude a greater distance exists be- 
  tween the generating source of the pressure 
  disturbance and the ground 
  level and the 
  strength of the wave will have a greater dis- 
  tance in which to decay. The ordinary vari- 
  temperature and density plus the 
  ation of 
  tend to 
  natural turbulence of atmosphere will 
  reflect or dissipate the shock wave generated 
  at high altitude. However, in a stable, quies- 
  cent atmosphere, the pressure wave from the 
  airplane in high supersonic flight at high alti- 
  tude may be of an audible magnitude at lateral 
  distances as great as 10 to 30 miles. Thus, 
  supersonic flight over or adjacent to populated 
  areas will produce a sonic boom. 
  
  Sound is transmitted 