Seismic and Underwater Responses to Sonic Boom

Sonic booms produced by aircraft moving at supersonic speeds apply moving loads to the earth. The deformation of a layered half‐space depends on the seismic surface‐wave modes. Those modes are selected which have phase velocities equal to the load speed. Dunkin and Corbin (1970) have shown theoretically that, in addition, the deformation contains terms that reduce to the static deformation as the load speed tends toward zero. Espinosa, Sierra, and Micky (1968) were able to relate experimentally observed low‐frequency seismic wavetrains to some of the trapped (normal) seismic modes. McDonald and Goforth (1969), using seismograph systems with broader frequency response in 178 NASA tests, were able to identify the two dominant high‐frequency peaks of the sonic boom seismic signature as the deformation resulting from the two rapid pressure changes associated with the N wave, to identify a fundamental air‐coupled Rayleigh wavetrain, to show that peak ground motion is proportional to sonic boom overpressure, an...