Method and apparatus for producing shear waves for subsurface geophysical investigation

摘要

Two or a larger even number of compressional wave producing vibrators are symmetrically disposed in two groups on opposite sides of a profile line in closely spaced relationship. The vibrators are energized by the same (or identical) sweep signals, the signals to one vibrator (or group) on one side of the line being separated in phase by 180° from the signals to the vibrator or group on the other side. P-wave components are thereby cancelled, leaving the shear waves to be propagated.