Ground vibration near explosions

One would expect that, since seismic waves from explosions are the basis of a whole industry (seismic surveying), their nature would have been throughly investigated and described. However, the exploration geophysicist is not primarily interested in the nature of the seismic pulses, but in their velocities and the paths they travel to his recording instruments. It is common practice in studying seismic exploration records to assume that only compressional pulses are clearly recorded, though occasionally the presence of some transverse wave energy is postulated to explain otherwise incomprehensible observations. Other types of wave motion are treated as part of the background noise, and wherever possible are excluded from the recorded spectrum by the use of appropriate filters in the amplifiers